Inital commit

78 files changed, 7473 insertions, 0 deletions

diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/AnimationTrackKeyDataSource.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/AnimationTrackKeyDataSource.cs
new file mode 100644
index 0000000..38c2f81
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/AnimationTrackKeyDataSource.cs
@@ -0,0 +1,25 @@
+using UnityEngine;
+using UnityEngine.Timeline;
+
+// Data sources for key overlays
+namespace UnityEditor.Timeline
+{
+    // Used for key overlays manipulators
+    class AnimationTrackKeyDataSource : BasePropertyKeyDataSource
+    {
+        readonly float m_TrackOffset;
+
+        protected override AnimationClip animationClip { get; }
+
+        public AnimationTrackKeyDataSource(AnimationTrack track)
+        {
+            animationClip = track != null ? track.infiniteClip : null;
+            m_TrackOffset = track != null ? (float)track.infiniteClipTimeOffset : 0.0f;
+        }
+
+        protected override float TransformKeyTime(float keyTime)
+        {
+            return keyTime + m_TrackOffset;
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/AnimationTrackKeyDataSource.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/AnimationTrackKeyDataSource.cs.meta
new file mode 100644
index 0000000..3c81758
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/AnimationTrackKeyDataSource.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: a0b56195e00682b4594dfaeef9d5fa78
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Control.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Control.cs
new file mode 100644
index 0000000..8788058
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Control.cs
@@ -0,0 +1,28 @@
+using System.Collections.Generic;
+
+namespace UnityEditor.Timeline
+{
+    class Control
+    {
+        readonly List<Manipulator> m_Manipulators = new List<Manipulator>();
+
+        public bool HandleManipulatorsEvents(WindowState state)
+        {
+            var isHandled = false;
+
+            foreach (var manipulator in m_Manipulators)
+            {
+                isHandled = manipulator.HandleEvent(state);
+                if (isHandled)
+                    break;
+            }
+
+            return isHandled;
+        }
+
+        public void AddManipulator(Manipulator m)
+        {
+            m_Manipulators.Add(m);
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Control.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Control.cs.meta
new file mode 100644
index 0000000..71c8d33
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Control.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 077690d334440b044bdd51b26b3e9413
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers.meta
new file mode 100644
index 0000000..a7ad23a
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers.meta
@@ -0,0 +1,8 @@
+fileFormatVersion: 2
+guid: d40a0edbdcdcf9747a420f3bbe0f18db
+folderAsset: yes
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/AnimationTrackDrawer.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/AnimationTrackDrawer.cs
new file mode 100644
index 0000000..0e9ef89
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/AnimationTrackDrawer.cs
@@ -0,0 +1,86 @@
+using System;
+using System.ComponentModel;
+using System.Linq;
+using JetBrains.Annotations;
+using UnityEngine;
+using UnityEditor;
+using UnityEngine.Timeline;
+
+namespace UnityEditor.Timeline
+{
+    [CustomTrackDrawer(typeof(AnimationTrack)), UsedImplicitly]
+    class AnimationTrackDrawer : TrackDrawer
+    {
+        internal static class Styles
+        {
+            public static readonly GUIContent AnimationButtonOnTooltip = EditorGUIUtility.TrTextContent("", "Avatar Mask enabled\nClick to disable");
+            public static readonly GUIContent AnimationButtonOffTooltip = EditorGUIUtility.TrTextContent("", "Avatar Mask disabled\nClick to enable");
+        }
+
+        public override bool DrawTrackHeaderButton(Rect rect, TrackAsset track, WindowState state)
+        {
+            var animTrack = track as AnimationTrack;
+            bool hasAvatarMask = animTrack != null && animTrack.avatarMask != null;
+            if (hasAvatarMask)
+            {
+                var style = animTrack.applyAvatarMask
+                    ? DirectorStyles.Instance.avatarMaskOn
+                    : DirectorStyles.Instance.avatarMaskOff;
+                var tooltip = animTrack.applyAvatarMask
+                    ? Styles.AnimationButtonOnTooltip
+                    : Styles.AnimationButtonOffTooltip;
+                if (GUI.Button(rect, tooltip, style))
+                {
+                    animTrack.applyAvatarMask = !animTrack.applyAvatarMask;
+                    if (state != null)
+                        state.rebuildGraph = true;
+                }
+            }
+            return hasAvatarMask;
+        }
+
+        public override void DrawRecordingBackground(Rect trackRect, TrackAsset trackAsset, Vector2 visibleTime, WindowState state)
+        {
+            base.DrawRecordingBackground(trackRect, trackAsset, visibleTime, state);
+            DrawBorderOfAddedRecordingClip(trackRect, trackAsset, visibleTime, (WindowState)state);
+        }
+
+        static void DrawBorderOfAddedRecordingClip(Rect trackRect, TrackAsset trackAsset, Vector2 visibleTime, WindowState state)
+        {
+            if (!state.IsArmedForRecord(trackAsset))
+                return;
+
+            AnimationTrack animTrack = trackAsset as AnimationTrack;
+            if (animTrack == null || !animTrack.inClipMode)
+                return;
+
+            // make sure there is no clip but we can add one
+            TimelineClip clip = null;
+            if (trackAsset.FindRecordingClipAtTime(state.editSequence.time, out clip) || clip != null)
+                return;
+
+            float yMax = trackRect.yMax;
+            float yMin = trackRect.yMin;
+
+            double startGap = 0;
+            double endGap = 0;
+
+            trackAsset.GetGapAtTime(state.editSequence.time, out startGap, out endGap);
+            if (double.IsInfinity(endGap))
+                endGap = visibleTime.y;
+
+            if (startGap > visibleTime.y || endGap < visibleTime.x)
+                return;
+
+
+            startGap = Math.Max(startGap, visibleTime.x);
+            endGap = Math.Min(endGap, visibleTime.y);
+
+            float xMin = state.TimeToPixel(startGap);
+            float xMax = state.TimeToPixel(endGap);
+
+            var r = Rect.MinMaxRect(xMin, yMin, xMax, yMax);
+            ClipDrawer.DrawClipSelectionBorder(r, ClipBorder.Recording(), ClipBlends.kNone);
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/AnimationTrackDrawer.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/AnimationTrackDrawer.cs.meta
new file mode 100644
index 0000000..20fed76
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/AnimationTrackDrawer.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: cb281723220c9964094e6c52e0ece792
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/ClipDrawer.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/ClipDrawer.cs
new file mode 100644
index 0000000..266e465
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/ClipDrawer.cs
@@ -0,0 +1,678 @@
+using System;
+using UnityEngine.Timeline;
+using UnityEngine;
+using System.Linq;
+using System.Collections.Generic;
+
+namespace UnityEditor.Timeline
+{
+    enum BlendKind
+    {
+        None,
+        Ease,
+        Mix
+    }
+
+    enum BlendAngle
+    {
+        Descending,
+        Ascending
+    }
+
+    struct IconData
+    {
+        public enum Side { Left = -1, Right = 1 }
+
+        public Texture2D icon;
+        public Color tint;
+
+        public float width { get { return 16; } }
+        public float height { get { return 16; } }
+
+        public IconData(Texture2D icon)
+        {
+            this.icon = icon;
+            tint = Color.white;
+        }
+    }
+
+    class ClipBorder
+    {
+        public readonly Color color;
+        public readonly float thickness;
+
+        ClipBorder(Color color, float thickness)
+        {
+            this.color = color;
+            this.thickness = thickness;
+        }
+
+        const float k_ClipSelectionBorder = 1.0f;
+        const float k_ClipRecordingBorder = 2.0f;
+
+        public static ClipBorder Recording()
+        {
+            return new ClipBorder(DirectorStyles.Instance.customSkin.colorRecordingClipOutline, k_ClipRecordingBorder);
+        }
+
+        public static ClipBorder Selection()
+        {
+            return new ClipBorder(Color.white, k_ClipSelectionBorder);
+        }
+
+        public static ClipBorder Default()
+        {
+            return new ClipBorder(DirectorStyles.Instance.customSkin.clipBorderColor, k_ClipSelectionBorder);
+        }
+    }
+
+    struct ClipBlends
+    {
+        public readonly BlendKind inKind;
+        public readonly Rect inRect;
+
+        public readonly BlendKind outKind;
+        public readonly Rect outRect;
+
+        public ClipBlends(BlendKind inKind, Rect inRect, BlendKind outKind, Rect outRect)
+        {
+            this.inKind = inKind;
+            this.inRect = inRect;
+            this.outKind = outKind;
+            this.outRect = outRect;
+        }
+
+        public static readonly ClipBlends kNone = new ClipBlends(BlendKind.None, Rect.zero, BlendKind.None, Rect.zero);
+    }
+
+    struct ClipDrawData
+    {
+        public TimelineClip clip;             // clip being drawn
+        public Rect targetRect;               // rectangle to draw to
+        public Rect unclippedRect;            // the clip's unclipped rect
+        public Rect clippedRect;              // the clip's clipped rect to the visible time area
+        public Rect clipCenterSection;        // clip center section
+        public string title;                  // clip title
+        public bool selected;                 // is the clip selected
+        public bool inlineCurvesSelected;     // is the inline curve of the clip selected
+        public double localVisibleStartTime;
+        public double localVisibleEndTime;
+        public IconData[] leftIcons;
+        public IconData[] rightIcons;
+        public TimelineClip previousClip;
+        public bool previousClipSelected;
+        public bool supportsLooping;
+        public int minLoopIndex;
+        public List<Rect> loopRects;
+        public ClipBlends clipBlends;
+        public ClipDrawOptions ClipDrawOptions;
+        public ClipEditor clipEditor;
+    }
+
+    static class ClipDrawer
+    {
+        public static class Styles
+        {
+            public static readonly Texture2D iconWarn = EditorGUIUtility.LoadIconRequired("console.warnicon.inactive.sml");
+            public static readonly string HoldText = LocalizationDatabase.GetLocalizedString("HOLD");
+            public static readonly Texture2D s_IconNoRecord = EditorGUIUtility.LoadIcon("console.erroricon.sml");
+            public static readonly GUIContent s_ClipNotRecorable = EditorGUIUtility.TrTextContent("", "This clip is not recordable");
+            public static readonly GUIContent s_ClipNoRecordInBlend = EditorGUIUtility.TrTextContent("", "Recording in blends in prohibited");
+        }
+
+        const float k_ClipSwatchLineThickness = 4.0f;
+        const float k_MinClipWidth = 7.0f;
+        const float k_ClipInOutMinWidth = 15.0f;
+        const float k_ClipLoopsMinWidth = 20.0f;
+        const float k_ClipLabelPadding = 6.0f;
+        const float k_ClipLabelMinWidth = 10.0f;
+        const float k_IconsPadding = 1.0f;
+        const float k_ClipInlineWidth = 1.0f;
+
+        static readonly GUIContent s_TitleContent = new GUIContent();
+        static readonly IconData[] k_ClipErrorIcons =  { new IconData {icon = Styles.iconWarn, tint = DirectorStyles.kClipErrorColor} };
+        static readonly Dictionary<int, string> s_LoopStringCache = new Dictionary<int, string>(100);
+
+        // caches the loopstring to avoid allocation from string concats
+        static string GetLoopString(int loopIndex)
+        {
+            string loopString = null;
+            if (!s_LoopStringCache.TryGetValue(loopIndex, out loopString))
+            {
+                loopString = "L" + loopIndex;
+                s_LoopStringCache[loopIndex] = loopString;
+            }
+            return loopString;
+        }
+
+        static void DrawLoops(ClipDrawData drawData)
+        {
+            if (drawData.loopRects == null || drawData.loopRects.Count == 0)
+                return;
+
+            var oldColor = GUI.color;
+
+            int loopIndex = drawData.minLoopIndex;
+            for (int l = 0; l < drawData.loopRects.Count; l++)
+            {
+                Rect theRect = drawData.loopRects[l];
+                theRect.x -= drawData.unclippedRect.x;
+                theRect.x += 1;
+                theRect.width -= 2.0f;
+                theRect.y = 5.0f;
+                theRect.height -= 4.0f;
+                theRect.xMin -= 4f;
+
+                if (theRect.width >= 5f)
+                {
+                    using (new GUIViewportScope(drawData.clipCenterSection))
+                    {
+                        GUI.color = new Color(0.0f, 0.0f, 0.0f, 0.2f);
+                        GUI.Label(theRect, GUIContent.none, DirectorStyles.Instance.displayBackground);
+
+                        if (theRect.width > 36.0f)
+                        {
+                            var style = DirectorStyles.Instance.fontClipLoop;
+                            GUI.color = new Color(0.0f, 0.0f, 0.0f, 0.3f);
+                            var loopContent = new GUIContent(drawData.supportsLooping ? GetLoopString(loopIndex) : Styles.HoldText);
+                            GUI.Label(theRect, loopContent, style);
+                        }
+                    }
+                }
+
+                loopIndex++;
+
+                if (!drawData.supportsLooping)
+                    break;
+            }
+
+            GUI.color = oldColor;
+        }
+
+        static void DrawClipBorder(ClipDrawData drawData)
+        {
+            var animTrack = drawData.clip.parentTrack as AnimationTrack;
+            var selectionBorder = ClipBorder.Selection();
+
+            if (TimelineWindow.instance.state.recording && animTrack == null && drawData.clip.parentTrack.IsRecordingToClip(drawData.clip))
+            {
+                DrawClipSelectionBorder(drawData.clipCenterSection, selectionBorder, drawData.clipBlends);
+                return;
+            }
+
+            DrawClipDefaultBorder(drawData.clipCenterSection, ClipBorder.Default(), drawData.clipBlends);
+
+            if (drawData.selected)
+                DrawClipSelectionBorder(drawData.clipCenterSection, selectionBorder, drawData.clipBlends);
+
+            if (drawData.previousClip != null && drawData.previousClipSelected)
+                DrawClipBlendSelectionBorder(drawData.clipCenterSection, selectionBorder, drawData.clipBlends);
+        }
+
+        public static void DrawClipSelectionBorder(Rect clipRect, ClipBorder border, ClipBlends blends)
+        {
+            var thickness = border.thickness;
+            var color = border.color;
+            var min = clipRect.min;
+            var max = clipRect.max;
+
+            //Left line
+            if (blends.inKind == BlendKind.None)
+                EditorGUI.DrawRect(new Rect(min.x, min.y, thickness, max.y - min.y), color);
+            else
+                DrawBlendLine(blends.inRect, blends.inKind == BlendKind.Mix ? BlendAngle.Descending : BlendAngle.Ascending, thickness, color);
+
+            //Right line
+            if (blends.outKind == BlendKind.None)
+                EditorGUI.DrawRect(new Rect(max.x - thickness, min.y, thickness, max.y - min.y), color);
+            else
+                DrawBlendLine(blends.outRect, BlendAngle.Descending, thickness, color);
+
+            //Top line
+            var xTop1 = blends.inKind == BlendKind.Mix ? blends.inRect.xMin : min.x;
+            var xTop2 = max.x;
+            EditorGUI.DrawRect(new Rect(xTop1, min.y, xTop2 - xTop1, thickness), color);
+
+            //Bottom line
+            var xBottom1 = blends.inKind == BlendKind.Ease ? blends.inRect.xMin : min.x;
+            var xBottom2 = blends.outKind == BlendKind.None ? max.x : blends.outRect.xMax;
+            EditorGUI.DrawRect(new Rect(xBottom1, max.y - thickness, xBottom2 - xBottom1, thickness), color);
+        }
+
+        static Vector3[] s_BlendLines = new Vector3[4];
+        static void DrawBlendLine(Rect rect, BlendAngle blendAngle, float width, Color color)
+        {
+            var halfWidth = width / 2.0f;
+            Vector2 p0, p1;
+            var inverse = 1.0f;
+            if (blendAngle == BlendAngle.Descending)
+            {
+                p0 = rect.min;
+                p1 = rect.max;
+            }
+            else
+            {
+                p0 = new Vector2(rect.xMax, rect.yMin);
+                p1 = new Vector2(rect.xMin, rect.yMax);
+                inverse = -1.0f;
+            }
+            s_BlendLines[0] = new Vector3(p0.x - halfWidth, p0.y + halfWidth * inverse);
+            s_BlendLines[1] = new Vector3(p1.x - halfWidth, p1.y + halfWidth * inverse);
+            s_BlendLines[2] = new Vector3(p1.x + halfWidth, p1.y - halfWidth * inverse);
+            s_BlendLines[3] = new Vector3(p0.x + halfWidth, p0.y - halfWidth * inverse);
+            Graphics.DrawPolygonAA(color, s_BlendLines);
+        }
+
+        static void DrawClipBlendSelectionBorder(Rect clipRect, ClipBorder border, ClipBlends blends)
+        {
+            var color = border.color;
+            var thickness = border.thickness;
+            if (blends.inKind == BlendKind.Mix)
+            {
+                DrawBlendLine(blends.inRect, BlendAngle.Descending, thickness, color);
+                var xBottom1 = blends.inRect.xMin;
+                var xBottom2 = blends.inRect.xMax;
+                EditorGUI.DrawRect(new Rect(xBottom1, clipRect.max.y - thickness, xBottom2 - xBottom1, thickness), color);
+            }
+        }
+
+        static void DrawClipDefaultBorder(Rect clipRect, ClipBorder border, ClipBlends blends)
+        {
+            var color = border.color;
+            var thickness = border.thickness;
+
+            // Draw vertical lines at the edges of the clip
+            EditorGUI.DrawRect(new Rect(clipRect.xMin, clipRect.y, thickness, clipRect.height), color); //left
+            //only draw the right one when no out mix blend
+            if (blends.outKind != BlendKind.Mix)
+                EditorGUI.DrawRect(new Rect(clipRect.xMax - thickness, clipRect.y, thickness, clipRect.height), color); //right
+            //draw a vertical line for the previous clip
+            if (blends.inKind == BlendKind.Mix)
+                EditorGUI.DrawRect(new Rect(blends.inRect.xMin, blends.inRect.y, thickness, blends.inRect.height), color); //left
+
+            //Draw blend line
+            if (blends.inKind == BlendKind.Mix)
+                DrawBlendLine(blends.inRect, BlendAngle.Descending, thickness, color);
+        }
+
+        static void DrawClipTimescale(Rect targetRect, Rect clippedRect, double timeScale)
+        {
+            if (timeScale != 1.0)
+            {
+                const float xOffset = 4.0f;
+                const float yOffset = 6.0f;
+                var segmentLength = timeScale > 1.0f ? 5.0f : 15.0f;
+
+                // clamp to the visible region to reduce the line count (case 1213189), but adject the start segment to match the visuals of drawing targetRect
+                var startX = clippedRect.min.x - ((clippedRect.min.x - targetRect.min.x) % (segmentLength*2));
+                var endX = clippedRect.max.x;
+
+                var start = new Vector3(startX + xOffset, targetRect.min.y + yOffset, 0.0f);
+                var end = new Vector3(endX - xOffset, targetRect.min.y + yOffset, 0.0f);
+
+                Graphics.DrawDottedLine(start, end, segmentLength, DirectorStyles.Instance.customSkin.colorClipFont);
+                Graphics.DrawDottedLine(start + new Vector3(0.0f, 1.0f, 0.0f), end + new Vector3(0.0f, 1.0f, 0.0f), segmentLength, DirectorStyles.Instance.customSkin.colorClipFont);
+            }
+        }
+
+        static void DrawClipInOut(Rect targetRect, TimelineClip clip)
+        {
+            var assetDuration = TimelineHelpers.GetClipAssetEndTime(clip);
+
+            bool drawClipOut = assetDuration<double.MaxValue &&
+                                             assetDuration - clip.end> TimeUtility.kTimeEpsilon;
+
+            bool drawClipIn = clip.clipIn > 0.0;
+
+            if (!drawClipIn && !drawClipOut)
+                return;
+
+            var rect = targetRect;
+
+            if (drawClipOut)
+            {
+                var icon = DirectorStyles.Instance.clipOut;
+                var iconRect = new Rect(rect.xMax - icon.fixedWidth - 2.0f,
+                    rect.yMin + (rect.height - icon.fixedHeight) * 0.5f,
+                    icon.fixedWidth, icon.fixedHeight);
+
+                GUI.Label(iconRect, GUIContent.none, icon);
+            }
+
+            if (drawClipIn)
+            {
+                var icon = DirectorStyles.Instance.clipIn;
+                var iconRect = new Rect(2.0f + rect.xMin,
+                    rect.yMin + (rect.height - icon.fixedHeight) * 0.5f,
+                    icon.fixedWidth, icon.fixedHeight);
+
+                GUI.Label(iconRect, GUIContent.none, icon);
+            }
+        }
+
+        static void DrawClipLabel(ClipDrawData data, Rect availableRect, Color color)
+        {
+            var errorText = data.ClipDrawOptions.errorText;
+            var hasError = !string.IsNullOrEmpty(errorText);
+            var textColor = hasError ? DirectorStyles.kClipErrorColor : color;
+            var tooltip = hasError ? errorText : data.ClipDrawOptions.tooltip;
+
+            if (hasError)
+                DrawClipLabel(data.title, availableRect, textColor, k_ClipErrorIcons, null, tooltip);
+            else
+                DrawClipLabel(data.title, availableRect, textColor, data.leftIcons, data.rightIcons, tooltip);
+        }
+
+        static void DrawClipLabel(string title, Rect availableRect, Color color, string errorText = "")
+        {
+            var hasError = !string.IsNullOrEmpty(errorText);
+            var textColor = hasError ? DirectorStyles.kClipErrorColor : color;
+
+            if (hasError)
+                DrawClipLabel(title, availableRect, textColor, k_ClipErrorIcons, null, errorText);
+            else
+                DrawClipLabel(title, availableRect, textColor, null, null, errorText);
+        }
+
+        static void DrawClipLabel(string title, Rect availableRect, Color textColor, IconData[] leftIcons, IconData[] rightIcons, string tooltipMessage = "")
+        {
+            s_TitleContent.text = title;
+            var neededTextWidth = DirectorStyles.Instance.fontClip.CalcSize(s_TitleContent).x;
+            var neededIconWidthLeft = 0.0f;
+            var neededIconWidthRight = 0.0f;
+
+            if (leftIcons != null)
+                for (int i = 0, n = leftIcons.Length; i < n; ++i)
+                    neededIconWidthLeft += leftIcons[i].width + k_IconsPadding;
+
+            if (rightIcons != null)
+                for (int i = 0, n = rightIcons.Length; i < n; ++i)
+                    neededIconWidthRight += rightIcons[i].width + k_IconsPadding;
+
+            var neededIconWidth = Mathf.Max(neededIconWidthLeft, neededIconWidthRight);
+
+            // Atomic operation: We either show all icons or no icons at all
+            var showIcons = neededTextWidth / 2.0f + neededIconWidth < availableRect.width / 2.0f;
+
+            if (showIcons)
+            {
+                if (leftIcons != null)
+                    DrawClipIcons(leftIcons, IconData.Side.Left, neededTextWidth, availableRect);
+
+                if (rightIcons != null)
+                    DrawClipIcons(rightIcons, IconData.Side.Right, neededTextWidth, availableRect);
+            }
+
+            if (neededTextWidth > availableRect.width)
+                s_TitleContent.text = DirectorStyles.Elipsify(title, availableRect.width, neededTextWidth);
+
+            s_TitleContent.tooltip = tooltipMessage;
+            DrawClipName(availableRect, s_TitleContent, textColor);
+        }
+
+        static void DrawClipIcons(IconData[] icons, IconData.Side side, float labelWidth, Rect availableRect)
+        {
+            var halfText = labelWidth / 2.0f;
+            var offset = halfText + k_IconsPadding;
+
+            foreach (var iconData in icons)
+            {
+                offset += iconData.width / 2.0f + k_IconsPadding;
+
+                var iconRect =
+                    new Rect(0.0f, 0.0f, iconData.width, iconData.height)
+                {
+                    center = new Vector2(availableRect.center.x + offset * (int)side, availableRect.center.y)
+                };
+
+                DrawIcon(iconRect, iconData.tint, iconData.icon);
+
+                offset += iconData.width / 2.0f;
+            }
+        }
+
+        static void DrawClipName(Rect rect, GUIContent content, Color textColor)
+        {
+            Graphics.ShadowLabel(rect, content, DirectorStyles.Instance.fontClip, textColor, Color.black);
+        }
+
+        static void DrawIcon(Rect imageRect, Color color, Texture2D icon)
+        {
+            GUI.DrawTexture(imageRect, icon, ScaleMode.ScaleAndCrop, true, 0, color, 0, 0);
+        }
+
+        static void DrawClipBackground(Rect clipCenterSection, bool selected)
+        {
+            if (Event.current.type != EventType.Repaint)
+                return;
+
+            var color = selected ? DirectorStyles.Instance.customSkin.clipSelectedBckg : DirectorStyles.Instance.customSkin.clipBckg;
+            EditorGUI.DrawRect(clipCenterSection, color);
+        }
+
+        static Vector3[] s_BlendVertices = new Vector3[3];
+        static void DrawClipBlends(ClipBlends blends, Color inColor, Color outColor, Color backgroundColor)
+        {
+            switch (blends.inKind)
+            {
+                case BlendKind.Ease:
+                    //     2
+                    //   / |
+                    //  /  |
+                    // 0---1
+                    EditorGUI.DrawRect(blends.inRect, backgroundColor);
+                    s_BlendVertices[0] = new Vector3(blends.inRect.xMin, blends.inRect.yMax);
+                    s_BlendVertices[1] = new Vector3(blends.inRect.xMax, blends.inRect.yMax);
+                    s_BlendVertices[2] = new Vector3(blends.inRect.xMax, blends.inRect.yMin);
+                    Graphics.DrawPolygonAA(inColor, s_BlendVertices);
+                    break;
+                case BlendKind.Mix:
+                    // 0---2
+                    //  \  |
+                    //   \ |
+                    //     1
+                    s_BlendVertices[0] = new Vector3(blends.inRect.xMin, blends.inRect.yMin);
+                    s_BlendVertices[1] = new Vector3(blends.inRect.xMax, blends.inRect.yMax);
+                    s_BlendVertices[2] = new Vector3(blends.inRect.xMax, blends.inRect.yMin);
+                    Graphics.DrawPolygonAA(inColor, s_BlendVertices);
+                    break;
+            }
+
+            if (blends.outKind != BlendKind.None)
+            {
+                if (blends.outKind == BlendKind.Ease)
+                    EditorGUI.DrawRect(blends.outRect, backgroundColor);
+                // 0
+                // | \
+                // |  \
+                // 1---2
+                s_BlendVertices[0] = new Vector3(blends.outRect.xMin, blends.outRect.yMin);
+                s_BlendVertices[1] = new Vector3(blends.outRect.xMin, blends.outRect.yMax);
+                s_BlendVertices[2] = new Vector3(blends.outRect.xMax, blends.outRect.yMax);
+                Graphics.DrawPolygonAA(outColor, s_BlendVertices);
+            }
+        }
+
+        static void DrawClipSwatch(Rect targetRect, Color swatchColor)
+        {
+            // Draw Colored Line at the bottom.
+            var colorRect = targetRect;
+            colorRect.yMin = colorRect.yMax - k_ClipSwatchLineThickness;
+            EditorGUI.DrawRect(colorRect, swatchColor);
+        }
+
+        public static void DrawSimpleClip(TimelineClip clip, Rect targetRect, ClipBorder border, Color overlay, ClipDrawOptions drawOptions)
+        {
+            GUI.BeginClip(targetRect);
+            var clipRect = new Rect(0.0f, 0.0f, targetRect.width, targetRect.height);
+
+            var orgColor = GUI.color;
+            GUI.color = overlay;
+
+            DrawClipBackground(clipRect, false);
+            GUI.color = orgColor;
+
+            if (clipRect.width <= k_MinClipWidth)
+            {
+                clipRect.width = k_MinClipWidth;
+            }
+
+            DrawClipSwatch(targetRect, drawOptions.highlightColor * overlay);
+
+            if (targetRect.width >= k_ClipInOutMinWidth)
+                DrawClipInOut(clipRect, clip);
+
+            var textRect = clipRect;
+
+            textRect.xMin += k_ClipLabelPadding;
+            textRect.xMax -= k_ClipLabelPadding;
+
+            if (textRect.width > k_ClipLabelMinWidth)
+                DrawClipLabel(clip.displayName, textRect, Color.white, drawOptions.errorText);
+
+            if (border != null)
+                DrawClipSelectionBorder(clipRect, border, ClipBlends.kNone);
+
+            GUI.EndClip();
+        }
+
+        public static void DrawDefaultClip(ClipDrawData drawData)
+        {
+            var customSkin = DirectorStyles.Instance.customSkin;
+            var blendInColor = drawData.selected ? customSkin.clipBlendInSelected : customSkin.clipBlendIn;
+            var blendOutColor = drawData.selected ? customSkin.clipBlendOutSelected : customSkin.clipBlendOut;
+            var easeBackgroundColor = customSkin.clipEaseBckgColor;
+
+            DrawClipBlends(drawData.clipBlends, blendInColor, blendOutColor, easeBackgroundColor);
+            DrawClipBackground(drawData.clipCenterSection, drawData.selected);
+
+            if (drawData.targetRect.width > k_MinClipWidth)
+            {
+                DrawClipEditorBackground(drawData);
+            }
+            else
+            {
+                drawData.targetRect.width = k_MinClipWidth;
+                drawData.clipCenterSection.width = k_MinClipWidth;
+            }
+
+            DrawClipTimescale(drawData.targetRect, drawData.clippedRect, drawData.clip.timeScale);
+
+            if (drawData.targetRect.width >= k_ClipInOutMinWidth)
+                DrawClipInOut(drawData.targetRect, drawData.clip);
+
+            var labelRect = drawData.clipCenterSection;
+
+            if (drawData.targetRect.width >= k_ClipLoopsMinWidth)
+            {
+                bool selected = drawData.selected || drawData.inlineCurvesSelected;
+
+                if (selected)
+                {
+                    if (drawData.loopRects != null && drawData.loopRects.Any())
+                    {
+                        DrawLoops(drawData);
+
+                        var l = drawData.loopRects[0];
+                        labelRect.xMax = Math.Min(labelRect.xMax, l.x - drawData.unclippedRect.x);
+                    }
+                }
+            }
+
+            labelRect.xMin += k_ClipLabelPadding;
+            labelRect.xMax -= k_ClipLabelPadding;
+
+            if (labelRect.width > k_ClipLabelMinWidth)
+            {
+                DrawClipLabel(drawData, labelRect, Color.white);
+            }
+
+            DrawClipSwatch(drawData.targetRect, drawData.ClipDrawOptions.highlightColor);
+            DrawClipBorder(drawData);
+        }
+
+        static void DrawClipEditorBackground(ClipDrawData drawData)
+        {
+            var isRepaint = (Event.current.type == EventType.Repaint);
+            if (isRepaint && drawData.clipEditor != null)
+            {
+                var customBodyRect = drawData.clippedRect;
+                customBodyRect.yMin += k_ClipInlineWidth;
+                customBodyRect.yMax -= k_ClipSwatchLineThickness;
+                var region = new ClipBackgroundRegion(customBodyRect, drawData.localVisibleStartTime, drawData.localVisibleEndTime);
+                try
+                {
+                    drawData.clipEditor.DrawBackground(drawData.clip, region);
+                }
+                catch (Exception e)
+                {
+                    Debug.LogException(e);
+                }
+            }
+        }
+
+        public static void DrawAnimationRecordBorder(ClipDrawData drawData)
+        {
+            if (!drawData.clip.parentTrack.IsRecordingToClip(drawData.clip))
+                return;
+
+            var time = new DiscreteTime(TimelineWindow.instance.state.editSequence.time);
+            var start = new DiscreteTime(drawData.clip.start + drawData.clip.mixInDuration);
+            var end = new DiscreteTime(drawData.clip.end - drawData.clip.mixOutDuration);
+
+            if (time < start || time >= end)
+                return;
+
+            DrawClipSelectionBorder(drawData.clipCenterSection, ClipBorder.Recording(), ClipBlends.kNone);
+        }
+
+        public static void DrawRecordProhibited(ClipDrawData drawData)
+        {
+            DrawRecordInvalidClip(drawData);
+            DrawRecordOnBlend(drawData);
+        }
+
+        public static void DrawRecordOnBlend(ClipDrawData drawData)
+        {
+            double time = TimelineWindow.instance.state.editSequence.time;
+            if (time >= drawData.clip.start && time < drawData.clip.start + drawData.clip.mixInDuration)
+            {
+                Rect r = Rect.MinMaxRect(drawData.clippedRect.xMin, drawData.clippedRect.yMin, drawData.clipCenterSection.xMin, drawData.clippedRect.yMax);
+                DrawInvalidRecordIcon(r, Styles.s_ClipNoRecordInBlend);
+            }
+
+            if (time <= drawData.clip.end && time > drawData.clip.end - drawData.clip.mixOutDuration)
+            {
+                Rect r = Rect.MinMaxRect(drawData.clipCenterSection.xMax, drawData.clippedRect.yMin, drawData.clippedRect.xMax, drawData.clippedRect.yMax);
+                DrawInvalidRecordIcon(r, Styles.s_ClipNoRecordInBlend);
+            }
+        }
+
+        public static void DrawRecordInvalidClip(ClipDrawData drawData)
+        {
+            if (drawData.clip.recordable)
+                return;
+
+            double time = TimelineWindow.instance.state.editSequence.time;
+            if (time < drawData.clip.start + drawData.clip.mixInDuration || time > drawData.clip.end - drawData.clip.mixOutDuration)
+                return;
+
+            DrawInvalidRecordIcon(drawData.clipCenterSection, Styles.s_ClipNotRecorable);
+        }
+
+        public static void DrawInvalidRecordIcon(Rect rect, GUIContent helpText)
+        {
+            EditorGUI.DrawRect(rect, new Color(0, 0, 0, 0.30f));
+
+            var icon = Styles.s_IconNoRecord;
+            if (rect.width < icon.width || rect.height < icon.height)
+                return;
+
+            float x = rect.x + (rect.width - icon.width) * 0.5f;
+            float y = rect.y + (rect.height - icon.height) * 0.5f;
+            Rect r = new Rect(x, y, icon.width, icon.height);
+            GUI.Label(r, helpText);
+            GUI.DrawTexture(r, icon, ScaleMode.ScaleAndCrop, true, 0, Color.white, 0, 0);
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/ClipDrawer.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/ClipDrawer.cs.meta
new file mode 100644
index 0000000..e1493e6
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/ClipDrawer.cs.meta
@@ -0,0 +1,11 @@
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+guid: 63118a0c9ee42ac46b7f30e793177a76
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/InfiniteTrackDrawer.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/InfiniteTrackDrawer.cs
new file mode 100644
index 0000000..b2c5d7f
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/InfiniteTrackDrawer.cs
@@ -0,0 +1,86 @@
+using UnityEngine;
+using UnityEngine.Timeline;
+
+namespace UnityEditor.Timeline
+{
+    class InfiniteTrackDrawer : TrackDrawer
+    {
+        readonly IPropertyKeyDataSource m_DataSource;
+        Rect m_TrackRect;
+
+        public InfiniteTrackDrawer(IPropertyKeyDataSource dataSource)
+        {
+            m_DataSource = dataSource;
+        }
+
+        public bool CanDraw(TrackAsset track, WindowState state)
+        {
+            var keys = m_DataSource.GetKeys();
+            var isTrackEmpty = track.clips.Length == 0;
+
+            return keys != null || (state.IsArmedForRecord(track) && isTrackEmpty);
+        }
+
+        static void DrawRecordBackground(Rect trackRect)
+        {
+            var styles = DirectorStyles.Instance;
+
+            EditorGUI.DrawRect(trackRect, styles.customSkin.colorInfiniteTrackBackgroundRecording);
+
+            Graphics.ShadowLabel(trackRect,
+                DirectorStyles.Elipsify(DirectorStyles.recordingLabel.text, trackRect, styles.fontClip),
+                styles.fontClip, Color.white, Color.black);
+        }
+
+        public override bool DrawTrack(Rect trackRect, TrackAsset trackAsset, Vector2 visibleTime, WindowState state)
+        {
+            m_TrackRect = trackRect;
+
+            if (!CanDraw(trackAsset, state))
+                return true;
+
+            if (state.recording && state.IsArmedForRecord(trackAsset))
+                DrawRecordBackground(trackRect);
+
+            GUI.Box(trackRect, GUIContent.none, DirectorStyles.Instance.infiniteTrack);
+
+            var shadowRect = trackRect;
+            shadowRect.yMin = shadowRect.yMax;
+            shadowRect.height = 15.0f;
+            if (Event.current.type == EventType.Repaint)
+                DirectorStyles.Instance.bottomShadow.Draw(shadowRect, false, false, false, false);
+
+            var keys = m_DataSource.GetKeys();
+            if (keys != null && keys.Length > 0)
+            {
+                foreach (var k in keys)
+                    DrawKeyFrame(k, state);
+            }
+
+            return true;
+        }
+
+        void DrawKeyFrame(float key, WindowState state)
+        {
+            var x = state.TimeToPixel(key);
+            var bounds = new Rect(x, m_TrackRect.yMin + 3.0f, 1.0f, m_TrackRect.height - 6.0f);
+
+            if (!m_TrackRect.Overlaps(bounds))
+                return;
+
+            var iconWidth = DirectorStyles.Instance.keyframe.fixedWidth;
+            var iconHeight = DirectorStyles.Instance.keyframe.fixedHeight;
+
+            var keyframeRect = bounds;
+            keyframeRect.width = iconWidth;
+            keyframeRect.height = iconHeight;
+            keyframeRect.xMin -= iconWidth / 2.0f;
+            keyframeRect.yMin = m_TrackRect.yMin + ((m_TrackRect.height - iconHeight) / 2.0f);
+
+            // case 890650 : Make sure to use GUI.Label and not GUI.Box since the number of key frames can vary while dragging keys in the inline curves causing hotControls to be desynchronized
+            GUI.Label(keyframeRect, GUIContent.none, DirectorStyles.Instance.keyframe);
+
+            EditorGUI.DrawRect(bounds, DirectorStyles.Instance.customSkin.colorInfiniteClipLine);
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/InfiniteTrackDrawer.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/InfiniteTrackDrawer.cs.meta
new file mode 100644
index 0000000..fd7c0b5
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/InfiniteTrackDrawer.cs.meta
@@ -0,0 +1,11 @@
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+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/Layers.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/Layers.meta
new file mode 100644
index 0000000..920cf3a
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/Layers.meta
@@ -0,0 +1,8 @@
+fileFormatVersion: 2
+guid: 16388ae022a89264b84107f0c1b44680
+folderAsset: yes
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/Layers/ClipsLayer.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/Layers/ClipsLayer.cs
new file mode 100644
index 0000000..910123e
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/Layers/ClipsLayer.cs
@@ -0,0 +1,57 @@
+using System.Collections.Generic;
+using System.Linq;
+using UnityEngine;
+using UnityEngine.Timeline;
+
+namespace UnityEditor.Timeline
+{
+    class ClipsLayer : ItemsLayer
+    {
+        static readonly GUIStyle k_ConnectorIcon = DirectorStyles.Instance.connector;
+
+        public ClipsLayer(Layer layerOrder, IRowGUI parent) : base(layerOrder)
+        {
+            var track = parent.asset;
+            track.SortClips();
+            TimelineClipGUI previousClipGUI = null;
+
+            foreach (var clip in track.clips)
+            {
+                var oldClipGUI = ItemToItemGui.GetGuiForClip(clip);
+                var isInvalid = oldClipGUI != null && oldClipGUI.isInvalid;  // HACK Make sure to carry invalidy state when refereshing the cache.
+
+                var currentClipGUI = new TimelineClipGUI(clip, parent, this) {isInvalid = isInvalid};
+                if (previousClipGUI != null) previousClipGUI.nextClip = currentClipGUI;
+                currentClipGUI.previousClip = previousClipGUI;
+                AddItem(currentClipGUI);
+                previousClipGUI = currentClipGUI;
+            }
+        }
+
+        public override void Draw(Rect rect, WindowState state)
+        {
+            base.Draw(rect, state); //draw clips
+            DrawConnector(items.OfType<TimelineClipGUI>());
+        }
+
+        static void DrawConnector(IEnumerable<TimelineClipGUI> clips)
+        {
+            if (Event.current.type != EventType.Repaint)
+                return;
+
+            foreach (var clip in clips)
+            {
+                if (clip.previousClip != null && clip.visible && clip.treeViewRect.width > 14 &&
+                    (DiscreteTime)clip.start == (DiscreteTime)clip.previousClip.end)
+                {
+                    // draw little connector widget
+                    var localRect = clip.treeViewRect;
+                    localRect.x -= Mathf.Floor(k_ConnectorIcon.fixedWidth / 2.0f);
+                    localRect.width = k_ConnectorIcon.fixedWidth;
+                    localRect.height = k_ConnectorIcon.fixedHeight;
+                    GUI.Label(localRect, GUIContent.none, k_ConnectorIcon);
+                }
+            }
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/Layers/ClipsLayer.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/Layers/ClipsLayer.cs.meta
new file mode 100644
index 0000000..58ef809
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/Layers/ClipsLayer.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: a809a4b50addbf44b9023b5e7f9fd4d2
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/Layers/ItemsLayer.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/Layers/ItemsLayer.cs
new file mode 100644
index 0000000..7446d59
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/Layers/ItemsLayer.cs
@@ -0,0 +1,134 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using UnityEngine;
+using UnityEngine.Timeline;
+
+namespace UnityEditor.Timeline
+{
+    enum Layer : byte
+    {
+        Clips,
+        ClipHandles,
+        Markers,
+        MarkerHeaderTrack,
+        MarkersOnHeader
+    }
+
+    struct LayerZOrder : IComparable<LayerZOrder>
+    {
+        Layer m_Layer;
+        int m_ZOrder;
+
+        public LayerZOrder(Layer layer, int zOrder)
+        {
+            m_Layer = layer;
+            m_ZOrder = zOrder;
+        }
+
+        public int CompareTo(LayerZOrder other)
+        {
+            if (m_Layer == other.m_Layer)
+                return m_ZOrder.CompareTo(other.m_ZOrder);
+            return m_Layer.CompareTo(other.m_Layer);
+        }
+
+        public static LayerZOrder operator++(LayerZOrder x)
+        {
+            return new LayerZOrder(x.m_Layer, x.m_ZOrder + 1);
+        }
+
+        public LayerZOrder ChangeLayer(Layer layer)
+        {
+            return new LayerZOrder(layer, m_ZOrder);
+        }
+    }
+
+    interface ILayerable
+    {
+        LayerZOrder zOrder { get; }
+    }
+
+    interface IZOrderProvider
+    {
+        LayerZOrder Next();
+    }
+
+    abstract class ItemsLayer : IZOrderProvider
+    {
+        // provide a buffer for time-based culling to allow for UI that extends slightly beyong the time (e.g. markers)
+        // prevents popping of marker visibility.
+        private const int kVisibilityBufferInPixels = 10;
+
+        int m_PreviousLayerStateHash = -1;
+        LayerZOrder m_LastZOrder;
+
+        public LayerZOrder Next()
+        {
+            return m_LastZOrder++;
+        }
+
+        readonly List<TimelineItemGUI> m_Items = new List<TimelineItemGUI>();
+        bool m_NeedSort = true;
+
+        public virtual void Draw(Rect rect, WindowState state)
+        {
+            if (!m_Items.Any()) return;
+
+            Sort();
+
+            // buffer to prevent flickering of markers at boundaries
+            var onePixelTime = state.PixelDeltaToDeltaTime(kVisibilityBufferInPixels);
+            var visibleTime = state.timeAreaShownRange + new Vector2(-onePixelTime, onePixelTime);
+            var layerViewStateHasChanged = GetLayerViewStateChanged(rect, state);
+
+            foreach (var item in m_Items)
+            {
+                item.visible = item.end > visibleTime.x && item.start < visibleTime.y;
+                if (!item.visible)
+                    continue;
+
+                item.Draw(rect, layerViewStateHasChanged, state);
+            }
+        }
+
+        public IEnumerable<TimelineItemGUI> items
+        {
+            get
+            {
+                return m_Items;
+            }
+        }
+
+        protected void AddItem(TimelineItemGUI item)
+        {
+            m_Items.Add(item);
+            m_NeedSort = true;
+        }
+
+        protected ItemsLayer(Layer layerOrder)
+        {
+            m_LastZOrder = new LayerZOrder(layerOrder, 0);
+        }
+
+        void Sort()
+        {
+            if (!m_NeedSort)
+                return;
+
+            m_Items.Sort((a, b) => a.zOrder.CompareTo(b.zOrder));
+            m_NeedSort = false;
+        }
+
+        bool GetLayerViewStateChanged(Rect rect, WindowState state)
+        {
+            var layerStateHash = rect.GetHashCode().CombineHash(state.viewStateHash);
+            var layerViewStateHasChanged = layerStateHash != m_PreviousLayerStateHash;
+
+            if (Event.current.type == EventType.Layout && layerViewStateHasChanged)
+                m_PreviousLayerStateHash = layerStateHash;
+
+            return layerViewStateHasChanged;
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/Layers/ItemsLayer.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/Layers/ItemsLayer.cs.meta
new file mode 100644
index 0000000..5ebff18
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/Layers/ItemsLayer.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: ef97f39912c138b4cabdccedfb24093b
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
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diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/Layers/MarkersLayer.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/Layers/MarkersLayer.cs
new file mode 100644
index 0000000..50d1432
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/Layers/MarkersLayer.cs
@@ -0,0 +1,80 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using UnityEngine.Timeline;
+
+namespace UnityEditor.Timeline
+{
+    class MarkersLayer : ItemsLayer
+    {
+        public MarkersLayer(Layer layerOrder, IRowGUI parent) : base(layerOrder)
+        {
+            CreateLists(parent);
+        }
+
+        void CreateLists(IRowGUI parent)
+        {
+            var markerCount = parent.asset.GetMarkerCount();
+            if (markerCount == 0) return;
+
+            var accumulator = new List<IMarker>();
+            var sortedMarkers = new List<IMarker>(parent.asset.GetMarkers());
+            var vm = TimelineWindowViewPrefs.GetTrackViewModelData(parent.asset);
+
+            sortedMarkers.Sort((lhs, rhs) =>
+            {
+                // Sort by time first
+                var timeComparison = lhs.time.CompareTo(rhs.time);
+                if (timeComparison != 0)
+                    return timeComparison;
+
+                // If there's a collision, sort by edit timestamp
+                var lhsObject = lhs as object;
+                var rhsObject = rhs as object;
+
+                if (lhsObject.Equals(null) || rhsObject.Equals(null))
+                    return 0;
+
+                var lhsHash = lhsObject.GetHashCode();
+                var rhsHash = rhsObject.GetHashCode();
+
+                if (vm.markerTimeStamps.ContainsKey(lhsHash) && vm.markerTimeStamps.ContainsKey(rhsHash))
+                    return vm.markerTimeStamps[lhsHash].CompareTo(vm.markerTimeStamps[rhsHash]);
+
+                return 0;
+            });
+
+            foreach (var current in sortedMarkers)
+            {
+                // TODO: Take zoom factor into account?
+                if (accumulator.Count > 0 && Math.Abs(current.time - accumulator[accumulator.Count - 1].time) > TimeUtility.kTimeEpsilon)
+                    ProcessAccumulator(accumulator, parent);
+
+                accumulator.Add(current);
+            }
+
+            ProcessAccumulator(accumulator, parent);
+        }
+
+        void ProcessAccumulator(List<IMarker> accumulator, IRowGUI parent)
+        {
+            if (accumulator.Count == 0) return;
+
+            if (accumulator.Count == 1)
+            {
+                AddItem(new TimelineMarkerGUI(accumulator[0], parent, this));
+            }
+            else
+            {
+                // Ensure that the cluster is always considered *below* the markers it contains.
+                var clusterZOrder = Next();
+                AddItem(
+                    new TimelineMarkerClusterGUI(
+                        accumulator.Select(m => new TimelineMarkerGUI(m, parent, this)).ToList(),
+                        parent, this, clusterZOrder));
+            }
+
+            accumulator.Clear();
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/Layers/MarkersLayer.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/Layers/MarkersLayer.cs.meta
new file mode 100644
index 0000000..32b0787
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/Layers/MarkersLayer.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: bea62e1faac8f9a48a4cb919ea05cb6a
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
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+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/TrackDrawer.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/TrackDrawer.cs
new file mode 100644
index 0000000..a29fefa
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/TrackDrawer.cs
@@ -0,0 +1,51 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using UnityEngine;
+using UnityEngine.Playables;
+using UnityEngine.Timeline;
+namespace UnityEditor.Timeline
+{
+    class TrackDrawer : GUIDrawer
+    {
+        internal WindowState sequencerState { get; set; }
+
+
+        public static TrackDrawer CreateInstance(TrackAsset trackAsset)
+        {
+            if (trackAsset == null)
+                return Activator.CreateInstance<TrackDrawer>();
+
+            TrackDrawer drawer;
+
+            try
+            {
+                drawer = (TrackDrawer)Activator.CreateInstance(TimelineHelpers.GetCustomDrawer(trackAsset.GetType()));
+            }
+            catch (Exception)
+            {
+                drawer = Activator.CreateInstance<TrackDrawer>();
+            }
+
+            drawer.track = trackAsset;
+            return drawer;
+        }
+
+        protected TrackAsset track { get; private set; }
+
+        public virtual bool DrawTrackHeaderButton(Rect rect, TrackAsset track, WindowState state)
+        {
+            return false;
+        }
+
+        public virtual bool DrawTrack(Rect trackRect, TrackAsset trackAsset, Vector2 visibleTime, WindowState state)
+        {
+            return false;
+        }
+
+        public virtual void DrawRecordingBackground(Rect trackRect, TrackAsset trackAsset, Vector2 visibleTime, WindowState state)
+        {
+            EditorGUI.DrawRect(trackRect, DirectorStyles.Instance.customSkin.colorTrackBackgroundRecording);
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/TrackDrawer.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/TrackDrawer.cs.meta
new file mode 100644
index 0000000..9588043
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/TrackDrawer.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 9a0f991b6c2f45b44b92e163f9969e8e
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/TrackItemsDrawer.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/TrackItemsDrawer.cs
new file mode 100644
index 0000000..677c2fe
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/TrackItemsDrawer.cs
@@ -0,0 +1,42 @@
+using System.Collections.Generic;
+using System.Linq;
+using UnityEngine;
+
+namespace UnityEditor.Timeline
+{
+    struct TrackItemsDrawer
+    {
+        List<ItemsLayer> m_Layers;
+        ClipsLayer m_ClipsLayer;
+
+        public IEnumerable<TimelineClipGUI> clips
+        {
+            get { return m_ClipsLayer.items.Cast<TimelineClipGUI>(); }
+        }
+
+        public TrackItemsDrawer(IRowGUI parent)
+        {
+            m_Layers = null;
+            m_ClipsLayer = null;
+            BuildGUICache(parent);
+        }
+
+        void BuildGUICache(IRowGUI parent)
+        {
+            m_ClipsLayer = new ClipsLayer(Layer.Clips, parent);
+            m_Layers = new List<ItemsLayer>
+            {
+                m_ClipsLayer,
+                new MarkersLayer(Layer.Markers, parent)
+            };
+        }
+
+        public void Draw(Rect rect, WindowState state)
+        {
+            foreach (var layer in m_Layers)
+            {
+                layer.Draw(rect, state);
+            }
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/TrackItemsDrawer.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/TrackItemsDrawer.cs.meta
new file mode 100644
index 0000000..d41923c
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Drawers/TrackItemsDrawer.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: c7137daaeb11e8647bf1ade9b7e9aa97
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/IPropertyKeyDataSource.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/IPropertyKeyDataSource.cs
new file mode 100644
index 0000000..a26deb6
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/IPropertyKeyDataSource.cs
@@ -0,0 +1,71 @@
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using UnityEditorInternal;
+using UnityEngine;
+
+namespace UnityEditor.Timeline
+{
+    interface IPropertyKeyDataSource
+    {
+        float[] GetKeys(); // Get the keys
+        Dictionary<float, string> GetDescriptions(); // Caches for descriptions
+    }
+
+    abstract class BasePropertyKeyDataSource : IPropertyKeyDataSource
+    {
+        static readonly StringBuilder k_StringBuilder = new StringBuilder();
+
+        protected abstract AnimationClip animationClip { get; }
+
+        public virtual float[] GetKeys()
+        {
+            if (animationClip == null)
+                return null;
+
+            var info =  AnimationClipCurveCache.Instance.GetCurveInfo(animationClip);
+            return info.keyTimes.Select(TransformKeyTime).ToArray();
+        }
+
+        public virtual Dictionary<float, string> GetDescriptions()
+        {
+            var map = new Dictionary<float, string>();
+            var info = AnimationClipCurveCache.Instance.GetCurveInfo(animationClip);
+            var processed = new HashSet<string>();
+
+            foreach (var b in info.bindings)
+            {
+                var groupID = b.GetGroupID();
+                if (processed.Contains(groupID))
+                    continue;
+
+                var group = info.GetGroupBinding(groupID);
+                var prefix = AnimationWindowUtility.GetNicePropertyGroupDisplayName(b.type, b.propertyName);
+
+                foreach (var t in info.keyTimes)
+                {
+                    k_StringBuilder.Length = 0;
+
+                    var key = TransformKeyTime(t);
+                    if (map.ContainsKey(key))
+                        k_StringBuilder.Append(map[key])
+                            .Append('\n');
+
+                    k_StringBuilder.Append(prefix)
+                        .Append(" : ")
+                        .Append(group.GetDescription(key));
+
+                    map[key] = k_StringBuilder.ToString();
+                }
+                processed.Add(groupID);
+            }
+
+            return map;
+        }
+
+        protected virtual float TransformKeyTime(float keyTime)
+        {
+            return keyTime;
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/IPropertyKeyDataSource.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/IPropertyKeyDataSource.cs.meta
new file mode 100644
index 0000000..4c8993c
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/IPropertyKeyDataSource.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: ee83d5e1ad2ac4c9aa39e3a6f256062e
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/IRowGUI.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/IRowGUI.cs
new file mode 100644
index 0000000..0745c6a
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/IRowGUI.cs
@@ -0,0 +1,16 @@
+using UnityEngine;
+using UnityEngine.Timeline;
+
+namespace UnityEditor.Timeline
+{
+    interface IRowGUI
+    {
+        TrackAsset asset { get; }
+        Rect boundingRect { get; }
+        bool locked { get; }
+        bool showMarkers { get; }
+        bool muted { get; }
+
+        Rect ToWindowSpace(Rect treeViewRect);
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/IRowGUI.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/IRowGUI.cs.meta
new file mode 100644
index 0000000..26dcaed
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/IRowGUI.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 5ecec8cdc3ff99e4a9c65635d7e6b043
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/InlineCurveEditor.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/InlineCurveEditor.cs
new file mode 100644
index 0000000..0bff23f
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/InlineCurveEditor.cs
@@ -0,0 +1,299 @@
+using System.Linq;
+using JetBrains.Annotations;
+using UnityEngine;
+using UnityEngine.Timeline;
+
+namespace UnityEditor.Timeline
+{
+    interface IClipCurveEditorOwner
+    {
+        ClipCurveEditor clipCurveEditor { get; }
+        bool inlineCurvesSelected { get; set; }
+        bool showLoops { get; }
+        TrackAsset owner { get; }
+    }
+
+    class InlineCurveResizeHandle : IBounds
+    {
+        public Rect boundingRect { get; private set; }
+
+        public TimelineTrackGUI trackGUI { get; }
+
+        public InlineCurveResizeHandle(TimelineTrackGUI trackGUI)
+        {
+            this.trackGUI = trackGUI;
+        }
+
+        public void Draw(Rect headerRect, Rect trackRect, WindowState state)
+        {
+            var rect = new Rect(headerRect.xMax + 4, headerRect.yMax - 5.0f, trackRect.width - 4, 5.0f);
+
+            var handleColor = Handles.color;
+            Handles.color = Color.black;
+            Handles.DrawAAPolyLine(1.0f,
+                new Vector3(rect.x, rect.yMax, 0.0f),
+                new Vector3(rect.xMax, rect.yMax, 0.0f));
+            Handles.color = handleColor;
+
+            EditorGUIUtility.AddCursorRect(rect, MouseCursor.SplitResizeUpDown);
+
+            boundingRect = trackGUI.ToWindowSpace(rect);
+
+            if (Event.current.type == EventType.Repaint)
+            {
+                state.spacePartitioner.AddBounds(this);
+
+                var dragStyle = new GUIStyle("RL DragHandle");
+                dragStyle.Draw(rect, GUIContent.none, false, false, false, false);
+            }
+        }
+    }
+
+    class InlineCurveEditor : IBounds
+    {
+        Rect m_TrackRect;
+        Rect m_HeaderRect;
+        readonly TimelineTrackGUI m_TrackGUI;
+        readonly InlineCurveResizeHandle m_ResizeHandle;
+
+        bool m_LastSelectionWasClip;
+        TimelineClipGUI m_LastSelectedClipGUI;
+
+        Rect IBounds.boundingRect { get { return m_TrackGUI.ToWindowSpace(m_TrackRect); } }
+
+        [UsedImplicitly] // Used in tests
+        public TimelineClipGUI currentClipGui
+        {
+            get { return m_LastSelectedClipGUI; }
+        }
+
+        public IClipCurveEditorOwner currentCurveEditor
+        {
+            get { return m_LastSelectionWasClip ? (IClipCurveEditorOwner)m_LastSelectedClipGUI : (IClipCurveEditorOwner)m_TrackGUI;  }
+        }
+
+        public InlineCurveEditor(TimelineTrackGUI trackGUI)
+        {
+            m_TrackGUI = trackGUI;
+            m_ResizeHandle = new InlineCurveResizeHandle(trackGUI);
+        }
+
+        static bool MouseOverTrackArea(Rect curveRect, Rect trackRect)
+        {
+            curveRect.y = trackRect.y;
+            curveRect.height = trackRect.height;
+
+            // clamp the curve editor to the track. this allows the menu to scroll properly
+            curveRect.xMin = Mathf.Max(curveRect.xMin, trackRect.xMin);
+            curveRect.xMax = trackRect.xMax;
+
+            return curveRect.Contains(Event.current.mousePosition);
+        }
+
+        static bool MouseOverHeaderArea(Rect headerRect, Rect trackRect)
+        {
+            headerRect.y = trackRect.y;
+            headerRect.height = trackRect.height;
+
+            return headerRect.Contains(Event.current.mousePosition);
+        }
+
+        static void DrawCurveEditor(IClipCurveEditorOwner clipCurveEditorOwner, WindowState state, Rect headerRect, Rect trackRect, Vector2 activeRange, bool locked)
+        {
+            ClipCurveEditor clipCurveEditor = clipCurveEditorOwner.clipCurveEditor;
+            CurveDataSource dataSource = clipCurveEditor.dataSource;
+            Rect curveRect = dataSource.GetBackgroundRect(state);
+
+            bool newlySelected = false;
+
+            if (Event.current.type == EventType.MouseDown || Event.current.type == EventType.ContextClick)
+                newlySelected = MouseOverTrackArea(curveRect, trackRect) || MouseOverHeaderArea(headerRect, trackRect);
+
+            // make sure to not use any event before drawing the curve.
+            bool prevEnabledState = GUI.enabled;
+            GUI.enabled = true;
+            clipCurveEditorOwner.clipCurveEditor.DrawHeader(headerRect);
+            GUI.enabled = prevEnabledState;
+
+            bool displayAsSelected = !locked && (clipCurveEditorOwner.inlineCurvesSelected || newlySelected);
+
+            using (new EditorGUI.DisabledScope(locked))
+                clipCurveEditor.DrawCurveEditor(trackRect, state, activeRange, clipCurveEditorOwner.showLoops, displayAsSelected);
+
+            if (newlySelected && !locked)
+            {
+                clipCurveEditorOwner.inlineCurvesSelected = true;
+                HandleCurrentEvent();
+            }
+        }
+
+        public void Draw(Rect headerRect, Rect trackRect, WindowState state)
+        {
+            m_TrackRect = trackRect;
+            m_TrackRect.height -= 5.0f;
+
+            if (Event.current.type == EventType.Repaint)
+                state.spacePartitioner.AddBounds(this);
+
+            // Remove the indentation of this track to render it properly, otherwise every GUI elements will be offsetted.
+            headerRect.x -= DirectorStyles.kBaseIndent;
+            headerRect.width += DirectorStyles.kBaseIndent;
+
+            // Remove the width of the color swatch.
+            headerRect.x += 4.0f;
+            headerRect.width -= 4.0f;
+
+            m_HeaderRect = headerRect;
+
+            EditorGUI.DrawRect(m_HeaderRect, DirectorStyles.Instance.customSkin.colorAnimEditorBinding);
+
+            if (ShouldShowClipCurves(state))
+            {
+                DrawCurveEditorsForClipsOnTrack(m_HeaderRect, m_TrackRect, state);
+            }
+            else if (ShouldShowTrackCurves())
+            {
+                DrawCurveEditorForTrack(m_HeaderRect, m_TrackRect, state);
+            }
+            else
+            {
+                DrawCurvesEditorForNothingSelected(m_HeaderRect, m_TrackRect, state);
+            }
+
+            m_ResizeHandle.Draw(headerRect, trackRect, state);
+
+            // If MouseDown or ContextClick are not consumed by the curves, use the event to prevent it from going deeper into the treeview.
+            if (Event.current.type == EventType.ContextClick)
+            {
+                var r = Rect.MinMaxRect(m_HeaderRect.xMin, m_HeaderRect.yMin, m_TrackRect.xMax, m_TrackRect.yMax);
+                if (r.Contains(Event.current.mousePosition))
+                    Event.current.Use();
+            }
+
+            UpdateViewModel();
+        }
+
+        public void Refresh()
+        {
+            if (m_LastSelectionWasClip)
+                RefreshInlineCurves(m_LastSelectedClipGUI);
+            else
+                RefreshInlineCurves(m_TrackGUI);
+        }
+
+        static void RefreshInlineCurves(IClipCurveEditorOwner guiItem)
+        {
+            if (guiItem.clipCurveEditor != null && guiItem.clipCurveEditor.dataSource != null)
+                guiItem.clipCurveEditor.dataSource.RebuildCurves();
+        }
+
+        void DrawCurveEditorForTrack(Rect headerRect, Rect trackRect, WindowState state)
+        {
+            if (m_TrackGUI.clipCurveEditor == null)
+                return;
+
+            var activeRange = new Vector2(state.TimeToPixel(0.0d), state.TimeToPixel(state.editSequence.duration));
+            DrawCurveEditor(m_TrackGUI, state, headerRect, trackRect, activeRange, m_TrackGUI.locked);
+            m_LastSelectionWasClip = false;
+        }
+
+        void DrawCurveEditorsForClipsOnTrack(Rect headerRect, Rect trackRect, WindowState state)
+        {
+            if (m_TrackGUI.clips.Count == 0)
+                return;
+
+            if (Event.current.type == EventType.Layout)
+            {
+                TimelineClipGUI selectedClip = SelectionManager.SelectedClipGUI().FirstOrDefault(x => x.parent == m_TrackGUI);
+                if (selectedClip != null)
+                {
+                    m_LastSelectedClipGUI = selectedClip;
+                }
+                else if (state.recording && state.IsArmedForRecord(m_TrackGUI.track))
+                {
+                    if (m_LastSelectedClipGUI == null || !m_TrackGUI.track.IsRecordingToClip(m_LastSelectedClipGUI.clip))
+                    {
+                        var clip = m_TrackGUI.clips.FirstOrDefault(x => m_TrackGUI.track.IsRecordingToClip(x.clip));
+                        if (clip != null)
+                            m_LastSelectedClipGUI = clip;
+                    }
+                }
+
+                if (m_LastSelectedClipGUI == null)
+                    m_LastSelectedClipGUI = m_TrackGUI.clips[0];
+            }
+
+            if (m_LastSelectedClipGUI == null || m_LastSelectedClipGUI.clipCurveEditor == null || m_LastSelectedClipGUI.isInvalid)
+                return;
+
+            var activeRange = new Vector2(state.TimeToPixel(m_LastSelectedClipGUI.clip.start), state.TimeToPixel(m_LastSelectedClipGUI.clip.end));
+            DrawCurveEditor(m_LastSelectedClipGUI, state, headerRect, trackRect, activeRange, m_TrackGUI.locked);
+            m_LastSelectionWasClip = true;
+        }
+
+        void DrawCurvesEditorForNothingSelected(Rect headerRect, Rect trackRect, WindowState state)
+        {
+            if (m_LastSelectionWasClip || !TrackHasCurvesToShow() && m_TrackGUI.clips.Count > 0)
+            {
+                DrawCurveEditorsForClipsOnTrack(headerRect, trackRect, state);
+            }
+            else
+            {
+                DrawCurveEditorForTrack(headerRect, trackRect, state);
+            }
+        }
+
+        bool ShouldShowClipCurves(WindowState state)
+        {
+            if (m_TrackGUI.clips.Count == 0)
+                return false;
+
+            // Is a clip selected or being recorded to?
+            return SelectionManager.SelectedClipGUI().FirstOrDefault(x => x.parent == m_TrackGUI) != null ||
+                state.recording && state.IsArmedForRecord(m_TrackGUI.track) && m_TrackGUI.clips.FirstOrDefault(x => m_TrackGUI.track.IsRecordingToClip(x.clip)) != null;
+        }
+
+        bool ShouldShowTrackCurves()
+        {
+            if (m_TrackGUI == null)
+                return false;
+
+            var isTrackSelected = SelectionManager.SelectedTrackGUI().FirstOrDefault(x => x == m_TrackGUI) != null;
+
+            if (!isTrackSelected)
+                return false;
+
+            return TrackHasCurvesToShow();
+        }
+
+        bool TrackHasCurvesToShow()
+        {
+            var animTrack = m_TrackGUI.track as AnimationTrack;
+            if (animTrack != null && !animTrack.inClipMode)
+                return true;
+
+            return m_TrackGUI.track.HasAnyAnimatableParameters();
+        }
+
+        void UpdateViewModel()
+        {
+            var curveEditor = currentCurveEditor.clipCurveEditor;
+            if (curveEditor == null || curveEditor.bindingHierarchy.treeViewController == null)
+                return;
+
+            var vm = TimelineWindowViewPrefs.GetTrackViewModelData(m_TrackGUI.track);
+            vm.inlineCurvesState = curveEditor.bindingHierarchy.treeViewController.state;
+            vm.inlineCurvesShownAreaInsideMargins = curveEditor.shownAreaInsideMargins;
+            vm.lastInlineCurveDataID = curveEditor.dataSource.id;
+        }
+
+        static void HandleCurrentEvent()
+        {
+#if UNITY_EDITOR_OSX
+            Event.current.type = EventType.Ignore;
+#else
+            Event.current.Use();
+#endif
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/InlineCurveEditor.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/InlineCurveEditor.cs.meta
new file mode 100644
index 0000000..cbc0b18
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/InlineCurveEditor.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: e1f640f1769d6274194cf97b0e24602c
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui.meta
new file mode 100644
index 0000000..f19c2d2
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui.meta
@@ -0,0 +1,8 @@
+fileFormatVersion: 2
+guid: 9d816a6ab06c6834480f5f45f440e287
+folderAsset: yes
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui/ISelectable.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui/ISelectable.cs
new file mode 100644
index 0000000..5f312c1
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui/ISelectable.cs
@@ -0,0 +1,11 @@
+using System;
+
+namespace UnityEditor.Timeline
+{
+    interface ISelectable : ILayerable
+    {
+        void Select();
+        bool IsSelected();
+        void Deselect();
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui/ISelectable.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui/ISelectable.cs.meta
new file mode 100644
index 0000000..970ecaa
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui/ISelectable.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 4acbfc0398bab674f922f693e58f4afc
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui/TimelineClipGUI.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui/TimelineClipGUI.cs
new file mode 100644
index 0000000..7d00228
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui/TimelineClipGUI.cs
@@ -0,0 +1,760 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using UnityEngine;
+using UnityEngine.Playables;
+using UnityEngine.Timeline;
+
+namespace UnityEditor.Timeline
+{
+    class TimelineClipGUI : TimelineItemGUI, IClipCurveEditorOwner, ISnappable, IAttractable
+    {
+        EditorClip m_EditorItem;
+
+        Rect m_ClipCenterSection;
+        readonly List<Rect> m_LoopRects = new List<Rect>();
+
+        ClipDrawData m_ClipDrawData;
+        Rect m_MixOutRect = new Rect();
+        Rect m_MixInRect = new Rect();
+        int m_MinLoopIndex = 1;
+
+        // clip dirty detection
+        int m_LastDirtyIndex = Int32.MinValue;
+        bool m_ClipViewDirty = true;
+
+        bool supportResize { get; }
+        public ClipCurveEditor clipCurveEditor { get; set; }
+        public TimelineClipGUI previousClip { get; set; }
+        public TimelineClipGUI nextClip { get; set; }
+
+        static readonly float k_MinMixWidth = 2;
+        static readonly float k_MaxHandleWidth = 10f;
+        static readonly float k_MinHandleWidth = 1f;
+
+        bool? m_ShowDrillIcon;
+        ClipEditor m_ClipEditor;
+
+        static List<PlayableDirector> s_TempSubDirectors = new List<PlayableDirector>();
+
+        static readonly IconData k_DiggableClipIcon = new IconData(DirectorStyles.LoadIcon("TimelineDigIn"));
+
+        string name
+        {
+            get
+            {
+                if (string.IsNullOrEmpty(clip.displayName))
+                    return "(Empty)";
+
+                return clip.displayName;
+            }
+        }
+
+        public bool inlineCurvesSelected
+        {
+            get { return SelectionManager.IsCurveEditorFocused(this); }
+            set
+            {
+                if (!value && SelectionManager.IsCurveEditorFocused(this))
+                    SelectionManager.SelectInlineCurveEditor(null);
+                else
+                    SelectionManager.SelectInlineCurveEditor(this);
+            }
+        }
+
+        public Rect mixOutRect
+        {
+            get
+            {
+                var percent = clip.mixOutPercentage;
+                var x = Mathf.Round(treeViewRect.width * (1 - percent));
+                var width = Mathf.Round(treeViewRect.width * percent);
+                m_MixOutRect.Set(x, 0.0f, width, treeViewRect.height);
+                return m_MixOutRect;
+            }
+        }
+
+        public Rect mixInRect
+        {
+            get
+            {
+                var width = Mathf.Round(treeViewRect.width * clip.mixInPercentage);
+                m_MixInRect.Set(0.0f, 0.0f, width, treeViewRect.height);
+                return m_MixInRect;
+            }
+        }
+
+        public ClipBlends GetClipBlends()
+        {
+            var _mixInRect = mixInRect;
+            var _mixOutRect = mixOutRect;
+
+            var blendInKind = BlendKind.None;
+            if (_mixInRect.width > k_MinMixWidth && clip.hasBlendIn)
+                blendInKind = BlendKind.Mix;
+            else if (_mixInRect.width > k_MinMixWidth)
+                blendInKind = BlendKind.Ease;
+
+            var blendOutKind = BlendKind.None;
+            if (_mixOutRect.width > k_MinMixWidth && clip.hasBlendOut)
+                blendOutKind = BlendKind.Mix;
+            else if (_mixOutRect.width > k_MinMixWidth)
+                blendOutKind = BlendKind.Ease;
+
+            return new ClipBlends(blendInKind, _mixInRect, blendOutKind, _mixOutRect);
+        }
+
+        public override double start
+        {
+            get { return clip.start; }
+        }
+
+        public override double end
+        {
+            get { return clip.end; }
+        }
+
+        public bool supportsLooping
+        {
+            get { return clip.SupportsLooping(); }
+        }
+
+        // for the inline curve editor, only show loops if we recorded the asset
+        bool IClipCurveEditorOwner.showLoops
+        {
+            get { return clip.SupportsLooping() && (clip.asset is AnimationPlayableAsset);  }
+        }
+
+        TrackAsset IClipCurveEditorOwner.owner
+        {
+            get { return clip.parentTrack; }
+        }
+
+        public bool supportsSubTimelines
+        {
+            get { return m_ClipEditor.supportsSubTimelines; }
+        }
+
+
+        public int minLoopIndex
+        {
+            get { return m_MinLoopIndex; }
+        }
+
+        public TrackDrawer drawer
+        {
+            get { return ((TimelineTrackGUI)parent).drawer; }
+        }
+
+        public Rect clippedRect { get; private set; }
+
+        public override void Select()
+        {
+            zOrder = zOrderProvider.Next();
+            SelectionManager.Add(clip);
+        }
+
+        public override bool IsSelected()
+        {
+            return SelectionManager.Contains(clip);
+        }
+
+        public override void Deselect()
+        {
+            SelectionManager.Remove(clip);
+        }
+
+        public override ITimelineItem item
+        {
+            get { return ItemsUtils.ToItem(clip); }
+        }
+
+        IZOrderProvider zOrderProvider { get; }
+
+        public TimelineClipHandle leftHandle { get; }
+        public TimelineClipHandle rightHandle { get; }
+
+        public TimelineClipGUI(TimelineClip clip, IRowGUI parent, IZOrderProvider provider) : base(parent)
+        {
+            zOrderProvider = provider;
+            zOrder = provider.Next();
+
+            m_EditorItem = EditorClipFactory.GetEditorClip(clip);
+            m_ClipEditor = CustomTimelineEditorCache.GetClipEditor(clip);
+
+            supportResize = true;
+
+            leftHandle = new TimelineClipHandle(this, TrimEdge.Start);
+            rightHandle = new TimelineClipHandle(this, TrimEdge.End);
+
+            ItemToItemGui.Add(clip, this);
+        }
+
+        void CreateInlineCurveEditor(WindowState state)
+        {
+            if (clipCurveEditor != null)
+                return;
+
+            var animationClip = clip.animationClip;
+
+            if (animationClip != null && animationClip.empty)
+                animationClip = null;
+
+            // prune out clips coming from FBX
+            if (animationClip != null && !clip.recordable)
+                return; // don't show, even if there are curves
+
+            if (animationClip == null && !clip.HasAnyAnimatableParameters())
+                return; // nothing to show
+
+            state.AddEndFrameDelegate((istate, currentEvent) =>
+            {
+                clipCurveEditor = new ClipCurveEditor(CurveDataSource.Create(this), TimelineWindow.instance, clip.parentTrack);
+                return true;
+            });
+        }
+
+        public TimelineClip clip
+        {
+            get { return m_EditorItem.clip; }
+        }
+
+        // Draw the actual clip. Defers to the track drawer for customization
+        void UpdateDrawData(WindowState state, Rect drawRect, string title, bool selected, bool previousClipSelected, float rectXOffset)
+        {
+            m_ClipDrawData.clip = clip;
+            m_ClipDrawData.targetRect = drawRect;
+            m_ClipDrawData.clipCenterSection = m_ClipCenterSection;
+            m_ClipDrawData.unclippedRect = treeViewRect;
+            m_ClipDrawData.title = title;
+            m_ClipDrawData.selected = selected;
+            m_ClipDrawData.inlineCurvesSelected = inlineCurvesSelected;
+            m_ClipDrawData.previousClip = previousClip != null ? previousClip.clip : null;
+            m_ClipDrawData.previousClipSelected = previousClipSelected;
+
+            Vector3 shownAreaTime = state.timeAreaShownRange;
+            m_ClipDrawData.localVisibleStartTime = clip.ToLocalTimeUnbound(Math.Max(clip.start, shownAreaTime.x));
+            m_ClipDrawData.localVisibleEndTime = clip.ToLocalTimeUnbound(Math.Min(clip.end, shownAreaTime.y));
+
+            m_ClipDrawData.clippedRect = new Rect(clippedRect.x - rectXOffset, 0.0f, clippedRect.width, clippedRect.height);
+
+            m_ClipDrawData.minLoopIndex = minLoopIndex;
+            m_ClipDrawData.loopRects = m_LoopRects;
+            m_ClipDrawData.supportsLooping = supportsLooping;
+            m_ClipDrawData.clipBlends = GetClipBlends();
+            m_ClipDrawData.clipEditor = m_ClipEditor;
+            m_ClipDrawData.ClipDrawOptions = UpdateClipDrawOptions(m_ClipEditor, clip);
+
+            UpdateClipIcons(state);
+        }
+
+        void UpdateClipIcons(WindowState state)
+        {
+            // Pass 1 - gather size
+            int required = 0;
+            bool requiresDigIn = ShowDrillIcon(state.editSequence.director);
+            if (requiresDigIn)
+                required++;
+
+            var icons = m_ClipDrawData.ClipDrawOptions.icons;
+            foreach (var icon in icons)
+            {
+                if (icon != null)
+                    required++;
+            }
+
+            // Pass 2 - copy icon data
+            if (required == 0)
+            {
+                m_ClipDrawData.rightIcons = null;
+                return;
+            }
+
+            if (m_ClipDrawData.rightIcons == null || m_ClipDrawData.rightIcons.Length != required)
+                m_ClipDrawData.rightIcons = new IconData[required];
+
+            int index = 0;
+            if (requiresDigIn)
+                m_ClipDrawData.rightIcons[index++] = k_DiggableClipIcon;
+
+            foreach (var icon in icons)
+            {
+                if (icon != null)
+                    m_ClipDrawData.rightIcons[index++] = new IconData(icon);
+            }
+        }
+
+        static ClipDrawOptions UpdateClipDrawOptions(ClipEditor clipEditor, TimelineClip clip)
+        {
+            try
+            {
+                return clipEditor.GetClipOptions(clip);
+            }
+            catch (Exception e)
+            {
+                Debug.LogException(e);
+            }
+
+            return CustomTimelineEditorCache.GetDefaultClipEditor().GetClipOptions(clip);
+        }
+
+        static void DrawClip(ClipDrawData drawData)
+        {
+            ClipDrawer.DrawDefaultClip(drawData);
+
+            if (drawData.clip.asset is AnimationPlayableAsset)
+            {
+                var state = TimelineWindow.instance.state;
+                if (state.recording && state.IsArmedForRecord(drawData.clip.parentTrack))
+                {
+                    ClipDrawer.DrawAnimationRecordBorder(drawData);
+                    ClipDrawer.DrawRecordProhibited(drawData);
+                }
+            }
+        }
+
+        public void DrawGhostClip(Rect targetRect)
+        {
+            DrawSimpleClip(targetRect, ClipBorder.Selection(), new Color(1.0f, 1.0f, 1.0f, 0.5f));
+        }
+
+        public void DrawInvalidClip(Rect targetRect)
+        {
+            DrawSimpleClip(targetRect, ClipBorder.Selection(), DirectorStyles.Instance.customSkin.colorInvalidClipOverlay);
+        }
+
+        void DrawSimpleClip(Rect targetRect, ClipBorder border, Color overlay)
+        {
+            var drawOptions = UpdateClipDrawOptions(CustomTimelineEditorCache.GetClipEditor(clip), clip);
+            ClipDrawer.DrawSimpleClip(clip, targetRect, border, overlay, drawOptions);
+        }
+
+        void DrawInto(Rect drawRect, WindowState state)
+        {
+            if (Event.current.type != EventType.Repaint)
+                return;
+
+            // create the inline curve editor if not already created
+            CreateInlineCurveEditor(state);
+
+            // @todo optimization, most of the calculations (rect, offsets, colors, etc.) could be cached
+            // and rebuilt when the hash of the clip changes.
+
+            if (isInvalid)
+            {
+                DrawInvalidClip(treeViewRect);
+                return;
+            }
+
+            GUI.BeginClip(drawRect);
+
+            var originRect = new Rect(0.0f, 0.0f, drawRect.width, drawRect.height);
+            string clipLabel = name;
+            var selected = SelectionManager.Contains(clip);
+            var previousClipSelected = previousClip != null && SelectionManager.Contains(previousClip.clip);
+
+            if (selected && 1.0 != clip.timeScale)
+                clipLabel += " " + clip.timeScale.ToString("F2") + "x";
+
+            UpdateDrawData(state, originRect, clipLabel, selected, previousClipSelected, drawRect.x);
+            DrawClip(m_ClipDrawData);
+
+            GUI.EndClip();
+
+            if (clip.parentTrack != null && !clip.parentTrack.lockedInHierarchy)
+            {
+                if (selected && supportResize)
+                {
+                    var cursorRect = rect;
+                    cursorRect.xMin += leftHandle.boundingRect.width;
+                    cursorRect.xMax -= rightHandle.boundingRect.width;
+                    EditorGUIUtility.AddCursorRect(cursorRect, MouseCursor.MoveArrow);
+                }
+
+                if (supportResize)
+                {
+                    var handleWidth = Mathf.Clamp(drawRect.width * 0.3f, k_MinHandleWidth, k_MaxHandleWidth);
+
+                    leftHandle.Draw(drawRect, handleWidth, state);
+                    rightHandle.Draw(drawRect, handleWidth, state);
+                }
+            }
+        }
+
+        void CalculateClipRectangle(Rect trackRect, WindowState state)
+        {
+            if (m_ClipViewDirty)
+            {
+                var clipRect = RectToTimeline(trackRect, state);
+                treeViewRect = clipRect;
+
+                // calculate clipped rect
+                clipRect.xMin = Mathf.Max(clipRect.xMin, trackRect.xMin);
+                clipRect.xMax = Mathf.Min(clipRect.xMax, trackRect.xMax);
+
+                if (clipRect.width > 0 && clipRect.width < 2)
+                {
+                    clipRect.width = 5.0f;
+                }
+
+                clippedRect = clipRect;
+            }
+        }
+
+        void AddToSpacePartitioner(WindowState state)
+        {
+            if (Event.current.type == EventType.Repaint && !parent.locked)
+                state.spacePartitioner.AddBounds(this, rect);
+        }
+
+        void CalculateBlendRect()
+        {
+            m_ClipCenterSection = treeViewRect;
+            m_ClipCenterSection.x = 0;
+            m_ClipCenterSection.y = 0;
+
+            m_ClipCenterSection.xMin = Mathf.Round(treeViewRect.width * clip.mixInPercentage);
+            m_ClipCenterSection.width = Mathf.Round(treeViewRect.width);
+            m_ClipCenterSection.xMax -= Mathf.Round(mixOutRect.width + treeViewRect.width * clip.mixInPercentage);
+        }
+
+        // Entry point to the Clip Drawing...
+        public override void Draw(Rect trackRect, bool trackRectChanged, WindowState state)
+        {
+            // if the clip has changed, fire the appropriate callback
+            DetectClipChanged(trackRectChanged);
+
+            // update the clip projected rectangle on the timeline
+            CalculateClipRectangle(trackRect, state);
+
+            AddToSpacePartitioner(state);
+
+            // update the blend rects (when clip overlaps with others)
+            CalculateBlendRect();
+
+            // update the loop rects (when clip loops)
+            CalculateLoopRects(trackRect, state);
+
+            DrawExtrapolation(trackRect, treeViewRect);
+
+            DrawInto(treeViewRect, state);
+
+            ResetClipChanged();
+        }
+
+        void DetectClipChanged(bool trackRectChanged)
+        {
+            if (Event.current.type == EventType.Layout)
+            {
+                if (clip.DirtyIndex != m_LastDirtyIndex)
+                {
+                    m_ClipViewDirty = true;
+
+                    try
+                    {
+                        m_ClipEditor.OnClipChanged(clip);
+                    }
+                    catch (Exception e)
+                    {
+                        Debug.LogException(e);
+                    }
+
+                    m_LastDirtyIndex = clip.DirtyIndex;
+                }
+                m_ClipViewDirty |= trackRectChanged;
+            }
+        }
+
+        void ResetClipChanged()
+        {
+            if (Event.current.type == EventType.Repaint)
+                m_ClipViewDirty = false;
+        }
+
+        GUIStyle GetExtrapolationIcon(TimelineClip.ClipExtrapolation mode)
+        {
+            GUIStyle extrapolationIcon = null;
+
+            switch (mode)
+            {
+                case TimelineClip.ClipExtrapolation.None: return null;
+                case TimelineClip.ClipExtrapolation.Hold: extrapolationIcon = m_Styles.extrapolationHold; break;
+                case TimelineClip.ClipExtrapolation.Loop: extrapolationIcon = m_Styles.extrapolationLoop; break;
+                case TimelineClip.ClipExtrapolation.PingPong: extrapolationIcon = m_Styles.extrapolationPingPong; break;
+                case TimelineClip.ClipExtrapolation.Continue: extrapolationIcon = m_Styles.extrapolationContinue; break;
+            }
+
+            return extrapolationIcon;
+        }
+
+        Rect GetPreExtrapolationBounds(Rect trackRect, Rect clipRect, GUIStyle icon)
+        {
+            float x = clipRect.xMin - (icon.fixedWidth + 10.0f);
+            float y = trackRect.yMin + (trackRect.height - icon.fixedHeight) / 2.0f;
+
+            if (previousClip != null)
+            {
+                float distance = Mathf.Abs(treeViewRect.xMin - previousClip.treeViewRect.xMax);
+
+                if (distance < icon.fixedWidth)
+                    return new Rect(0.0f, 0.0f, 0.0f, 0.0f);
+
+                if (distance < icon.fixedWidth + 20.0f)
+                {
+                    float delta = (distance - icon.fixedWidth) / 2.0f;
+                    x = clipRect.xMin - (icon.fixedWidth + delta);
+                }
+            }
+
+            return new Rect(x, y, icon.fixedWidth, icon.fixedHeight);
+        }
+
+        Rect GetPostExtrapolationBounds(Rect trackRect, Rect clipRect, GUIStyle icon)
+        {
+            float x = clipRect.xMax + 10.0f;
+            float y = trackRect.yMin + (trackRect.height - icon.fixedHeight) / 2.0f;
+
+            if (nextClip != null)
+            {
+                float distance = Mathf.Abs(nextClip.treeViewRect.xMin - treeViewRect.xMax);
+
+                if (distance < icon.fixedWidth)
+                    return new Rect(0.0f, 0.0f, 0.0f, 0.0f);
+
+                if (distance < icon.fixedWidth + 20.0f)
+                {
+                    float delta = (distance - icon.fixedWidth) / 2.0f;
+                    x = clipRect.xMax + delta;
+                }
+            }
+
+            return new Rect(x, y, icon.fixedWidth, icon.fixedHeight);
+        }
+
+        static void DrawExtrapolationIcon(Rect rect, GUIStyle icon)
+        {
+            GUI.Label(rect, GUIContent.none, icon);
+        }
+
+        void DrawExtrapolation(Rect trackRect, Rect clipRect)
+        {
+            if (clip.hasPreExtrapolation)
+            {
+                GUIStyle icon = GetExtrapolationIcon(clip.preExtrapolationMode);
+
+                if (icon != null)
+                {
+                    Rect iconBounds = GetPreExtrapolationBounds(trackRect, clipRect, icon);
+
+                    if (iconBounds.width > 1 && iconBounds.height > 1)
+                        DrawExtrapolationIcon(iconBounds, icon);
+                }
+            }
+
+            if (clip.hasPostExtrapolation)
+            {
+                GUIStyle icon = GetExtrapolationIcon(clip.postExtrapolationMode);
+
+                if (icon != null)
+                {
+                    Rect iconBounds = GetPostExtrapolationBounds(trackRect, clipRect, icon);
+
+                    if (iconBounds.width > 1 && iconBounds.height > 1)
+                        DrawExtrapolationIcon(iconBounds, icon);
+                }
+            }
+        }
+
+        static Rect ProjectRectOnTimeline(Rect rect, Rect trackRect, WindowState state)
+        {
+            Rect newRect = rect;
+            // transform clipRect into pixel-space
+            newRect.x *= state.timeAreaScale.x;
+            newRect.width *= state.timeAreaScale.x;
+
+            newRect.x += state.timeAreaTranslation.x + trackRect.xMin;
+
+            // adjust clipRect height and vertical centering
+            const int clipPadding = 2;
+            newRect.y = trackRect.y + clipPadding;
+            newRect.height = trackRect.height - (2 * clipPadding);
+            return newRect;
+        }
+
+        void CalculateLoopRects(Rect trackRect, WindowState state)
+        {
+            if (!m_ClipViewDirty)
+                return;
+
+            m_LoopRects.Clear();
+            if (clip.duration < WindowState.kTimeEpsilon)
+                return;
+
+            var times = TimelineHelpers.GetLoopTimes(clip);
+            var loopDuration = TimelineHelpers.GetLoopDuration(clip);
+            m_MinLoopIndex = -1;
+
+            // we have a hold, no need to compute all loops
+            if (!supportsLooping)
+            {
+                if (times.Length > 1)
+                {
+                    var t = times[1];
+                    float loopTime = (float)(clip.duration - t);
+                    m_LoopRects.Add(ProjectRectOnTimeline(new Rect((float)(t + clip.start), 0, loopTime, 0), trackRect, state));
+                }
+                return;
+            }
+
+            var range = state.timeAreaShownRange;
+            var visibleStartTime = range.x - clip.start;
+            var visibleEndTime = range.y - clip.start;
+
+            for (int i = 1; i < times.Length; i++)
+            {
+                var t = times[i];
+
+                // don't draw off screen loops
+                if (t > visibleEndTime)
+                    break;
+
+                float loopTime = Mathf.Min((float)(clip.duration - t), (float)loopDuration);
+                var loopEnd = t + loopTime;
+
+                if (loopEnd < visibleStartTime)
+                    continue;
+
+                m_LoopRects.Add(ProjectRectOnTimeline(new Rect((float)(t + clip.start), 0, loopTime, 0), trackRect, state));
+
+                if (m_MinLoopIndex == -1)
+                    m_MinLoopIndex = i;
+            }
+        }
+
+        public override Rect RectToTimeline(Rect trackRect, WindowState state)
+        {
+            var offsetFromTimeSpaceToPixelSpace = state.timeAreaTranslation.x + trackRect.xMin;
+
+            var start = (float)(DiscreteTime)clip.start;
+            var end = (float)(DiscreteTime)clip.end;
+
+            return Rect.MinMaxRect(
+                Mathf.Round(start * state.timeAreaScale.x + offsetFromTimeSpaceToPixelSpace), Mathf.Round(trackRect.yMin),
+                Mathf.Round(end * state.timeAreaScale.x + offsetFromTimeSpaceToPixelSpace), Mathf.Round(trackRect.yMax)
+            );
+        }
+
+        public IEnumerable<Edge> SnappableEdgesFor(IAttractable attractable, ManipulateEdges manipulateEdges)
+        {
+            var edges = new List<Edge>();
+
+            bool canAddEdges = !parent.muted;
+
+            if (canAddEdges)
+            {
+                // Hack: Trim Start in Ripple mode should not have any snap point added
+                if (EditMode.editType == EditMode.EditType.Ripple && manipulateEdges == ManipulateEdges.Left)
+                    return edges;
+
+                if (attractable != this)
+                {
+                    if (EditMode.editType == EditMode.EditType.Ripple)
+                    {
+                        bool skip = false;
+
+                        // Hack: Since Trim End and Move in Ripple mode causes other snap point to move on the same track (which is not supported), disable snapping for this special cases...
+                        // TODO Find a proper way to have different snap edges for each edit mode.
+                        if (manipulateEdges == ManipulateEdges.Right)
+                        {
+                            var otherClipGUI = attractable as TimelineClipGUI;
+                            skip = otherClipGUI != null && otherClipGUI.parent == parent;
+                        }
+                        else if (manipulateEdges == ManipulateEdges.Both)
+                        {
+                            var moveHandler = attractable as MoveItemHandler;
+                            skip = moveHandler != null && moveHandler.movingItems.Any(clips => clips.targetTrack == clip.parentTrack && clip.start >= clips.start);
+                        }
+
+                        if (skip)
+                            return edges;
+                    }
+
+                    AddEdge(edges, clip.start);
+                    AddEdge(edges, clip.end);
+                }
+                else
+                {
+                    if (manipulateEdges == ManipulateEdges.Right)
+                    {
+                        var d = TimelineHelpers.GetClipAssetEndTime(clip);
+
+                        if (d < double.MaxValue)
+                        {
+                            if (clip.SupportsLooping())
+                            {
+                                var l = TimelineHelpers.GetLoopDuration(clip);
+
+                                var shownTime = TimelineWindow.instance.state.timeAreaShownRange;
+                                do
+                                {
+                                    AddEdge(edges, d, false);
+                                    d += l;
+                                }
+                                while (d < shownTime.y);
+                            }
+                            else
+                            {
+                                AddEdge(edges, d, false);
+                            }
+                        }
+                    }
+
+                    if (manipulateEdges == ManipulateEdges.Left)
+                    {
+                        var clipInfo = AnimationClipCurveCache.Instance.GetCurveInfo(clip.animationClip);
+                        if (clipInfo != null && clipInfo.keyTimes.Any())
+                            AddEdge(edges, clip.FromLocalTimeUnbound(clipInfo.keyTimes.Min()), false);
+                    }
+                }
+            }
+            return edges;
+        }
+
+        public bool ShouldSnapTo(ISnappable snappable)
+        {
+            return true;
+        }
+
+        bool ShowDrillIcon(PlayableDirector resolver)
+        {
+            if (!m_ShowDrillIcon.HasValue || TimelineWindow.instance.hierarchyChangedThisFrame)
+            {
+                var nestable = m_ClipEditor.supportsSubTimelines;
+                m_ShowDrillIcon = nestable && resolver != null;
+                if (m_ShowDrillIcon.Value)
+                {
+                    s_TempSubDirectors.Clear();
+                    try
+                    {
+                        m_ClipEditor.GetSubTimelines(clip, resolver, s_TempSubDirectors);
+                    }
+                    catch (Exception e)
+                    {
+                        Debug.LogException(e);
+                    }
+
+                    m_ShowDrillIcon &= s_TempSubDirectors.Count > 0;
+                }
+            }
+
+            return m_ShowDrillIcon.Value;
+        }
+
+        static void AddEdge(List<Edge> edges, double time, bool showEdgeHint = true)
+        {
+            var shownTime = TimelineWindow.instance.state.timeAreaShownRange;
+            if (time >= shownTime.x && time <= shownTime.y)
+                edges.Add(new Edge(time, showEdgeHint));
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui/TimelineClipGUI.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui/TimelineClipGUI.cs.meta
new file mode 100644
index 0000000..4e94156
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui/TimelineClipGUI.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 3c01b61b3a6887c49a15276fd38be918
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui/TimelineItemGUI.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui/TimelineItemGUI.cs
new file mode 100644
index 0000000..522b35e
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui/TimelineItemGUI.cs
@@ -0,0 +1,92 @@
+using System;
+using System.Collections.Generic;
+using UnityEngine.Timeline;
+using UnityEngine;
+
+namespace UnityEditor.Timeline
+{
+    static class ItemToItemGui
+    {
+        static Dictionary<object, TimelineItemGUI> s_ItemToItemGUI =
+            new Dictionary<object, TimelineItemGUI>();
+
+        public static void Add(TimelineClip clip, TimelineItemGUI gui)
+        {
+            s_ItemToItemGUI[clip] = gui;
+        }
+
+        public static void Add(IMarker marker, TimelineItemGUI gui)
+        {
+            s_ItemToItemGUI[marker] = gui;
+        }
+
+        public static TimelineClipGUI GetGuiForClip(TimelineClip clip)
+        {
+            return GetGuiForItem(clip) as TimelineClipGUI;
+        }
+
+        public static TimelineMarkerGUI GetGuiForMarker(IMarker marker)
+        {
+            return GetGuiForItem(marker) as TimelineMarkerGUI;
+        }
+
+        static TimelineItemGUI GetGuiForItem(object item)
+        {
+            if (item == null)
+                return null;
+
+            TimelineItemGUI gui;
+            s_ItemToItemGUI.TryGetValue(item, out gui);
+            return gui;
+        }
+    }
+
+    abstract class TimelineItemGUI : ISelectable
+    {
+        protected readonly DirectorStyles m_Styles;
+
+        public abstract ITimelineItem item { get; }
+        public abstract double start { get; }
+        public abstract double end { get; }
+        public abstract void Draw(Rect rect, bool rectChanged, WindowState state);
+        public abstract Rect RectToTimeline(Rect trackRect, WindowState state);
+
+        public virtual void Select() {}
+        public virtual bool IsSelected() { return false; }
+        public virtual void Deselect() {}
+
+        public virtual void StartDrag() {}
+        public virtual void StopDrag() {}
+
+        public LayerZOrder zOrder { get; set; }
+
+        public bool visible { get; set; }
+        public bool isInvalid { get; set; }
+
+        public IRowGUI parent { get; }
+
+        public Rect rect
+        {
+            get { return parent.ToWindowSpace(treeViewRect); }
+        }
+
+        public Rect treeViewRect
+        {
+            get { return m_TreeViewRect; }
+            protected set
+            {
+                m_TreeViewRect = value;
+                if (value.width < 0.0f)
+                    m_TreeViewRect.width = 1.0f;
+            }
+        }
+
+        Rect m_TreeViewRect;
+
+        protected TimelineItemGUI(IRowGUI parent)
+        {
+            this.parent = parent;
+            m_Styles = DirectorStyles.Instance;
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui/TimelineItemGUI.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui/TimelineItemGUI.cs.meta
new file mode 100644
index 0000000..a38143d
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui/TimelineItemGUI.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 6f515f8ecd3b6a546b90abaae2553f99
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui/TimelineMarkerClusterGUI.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui/TimelineMarkerClusterGUI.cs
new file mode 100644
index 0000000..b0ffeac
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui/TimelineMarkerClusterGUI.cs
@@ -0,0 +1,150 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using UnityEngine;
+
+using UnityObject = UnityEngine.Object;
+
+namespace UnityEditor.Timeline
+{
+    class TimelineMarkerClusterGUI : TimelineItemGUI
+    {
+        readonly List<TimelineMarkerGUI> m_MarkerGUIs;
+        readonly IZOrderProvider m_ZOrderProvider;
+
+        public TimelineMarkerGUI topMarker
+        {
+            get { return m_MarkerGUIs.LastOrDefault(); }
+        }
+
+        TimelineMarkerGUI m_ManipulatedMarker;
+
+        public TimelineMarkerClusterGUI(List<TimelineMarkerGUI> guis, IRowGUI parent,
+                                        IZOrderProvider zOrderProvider, LayerZOrder layerZOrder)
+            : base(parent)
+        {
+            m_MarkerGUIs = guis;
+            m_ZOrderProvider = zOrderProvider;
+            zOrder = layerZOrder;
+            SortMarkers();
+            topMarker.onStartDrag += OnDragTopMarker;
+        }
+
+        public override double start
+        {
+            get { return topMarker.start; }
+        }
+
+        public override double end
+        {
+            get { return topMarker.end; }
+        }
+
+        public override ITimelineItem item
+        {
+            get { return topMarker.item; }
+        }
+
+        public override void Select()
+        {
+            foreach (var marker in m_MarkerGUIs)
+            {
+                if (!marker.IsSelected())
+                    marker.Select();
+            }
+        }
+
+        public override void Deselect()
+        {
+            foreach (var marker in m_MarkerGUIs)
+            {
+                if (marker.IsSelected())
+                    marker.Deselect();
+            }
+        }
+
+        public override void Draw(Rect trackRect, bool trackRectChanged, WindowState state)
+        {
+            RegisterRect(state);
+
+            topMarker.Draw(trackRect, trackRectChanged, state);
+
+            if (m_MarkerGUIs.Count > 1)
+                GUI.Box(treeViewRect, String.Empty, DirectorStyles.Instance.markerMultiOverlay);
+
+            if (m_ManipulatedMarker != null)
+                m_ManipulatedMarker.Draw(trackRect, trackRectChanged, state);
+        }
+
+        public override Rect RectToTimeline(Rect trackRect, WindowState state)
+        {
+            return topMarker.RectToTimeline(trackRect, state);
+        }
+
+        public void CycleTop()
+        {
+            if (m_MarkerGUIs.Count < 2)
+                return;
+
+            topMarker.onStartDrag -= OnDragTopMarker;
+
+            var last = topMarker;
+            for (int i = 0; i < m_MarkerGUIs.Count; ++i)
+            {
+                var next = m_MarkerGUIs[i];
+                m_MarkerGUIs[i] = last;
+                last = next;
+            }
+
+            topMarker.zOrder = m_ZOrderProvider.Next();
+
+            topMarker.onStartDrag += OnDragTopMarker;
+        }
+
+        void OnDragTopMarker()
+        {
+            m_ManipulatedMarker = topMarker;
+            m_ManipulatedMarker.onStartDrag -= OnDragTopMarker;
+            m_MarkerGUIs.RemoveAt(m_MarkerGUIs.Count - 1);
+        }
+
+        void SortMarkers()
+        {
+            m_MarkerGUIs.Sort((lhs, rhs) => lhs.zOrder.CompareTo(rhs.zOrder));
+        }
+
+        void RegisterRect(WindowState state)
+        {
+            treeViewRect = topMarker.treeViewRect;
+
+            if (Event.current.type == EventType.Repaint && !parent.locked)
+                state.spacePartitioner.AddBounds(this, rect);
+        }
+
+        public static bool CanCycleMarkers()
+        {
+            if (!SelectionManager.SelectedMarkers().Any())
+                return false;
+
+            var cluster = PickerUtils.PickedLayerableOfType<TimelineMarkerClusterGUI>();
+
+            if (cluster == null)
+                return false;
+
+            // Only cycle if the marker is selected and nothing else is selected
+            return cluster.topMarker.IsSelected() && SelectionManager.Count() == 1;
+        }
+
+        public static void CycleMarkers()
+        {
+            var cluster = PickerUtils.PickedLayerableOfType<TimelineMarkerClusterGUI>();
+
+            if (cluster == null)
+                return;
+
+            cluster.topMarker.Deselect();
+            cluster.CycleTop();
+            cluster.topMarker.Select();
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui/TimelineMarkerClusterGUI.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui/TimelineMarkerClusterGUI.cs.meta
new file mode 100644
index 0000000..692661f
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui/TimelineMarkerClusterGUI.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 2c03ae9aa36a4fd44a983831f44654be
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui/TimelineMarkerGUI.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui/TimelineMarkerGUI.cs
new file mode 100644
index 0000000..5f054f7
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui/TimelineMarkerGUI.cs
@@ -0,0 +1,193 @@
+using System;
+using System.Collections.Generic;
+using UnityEngine;
+using UnityEngine.Timeline;
+using UnityObject = UnityEngine.Object;
+
+namespace UnityEditor.Timeline
+{
+    class TimelineMarkerGUI : TimelineItemGUI, ISnappable, IAttractable
+    {
+        public event Action onStartDrag;
+
+        int m_ProjectedClipHash;
+        int m_MarkerHash;
+        bool m_Selectable;
+
+        MarkerDrawOptions m_MarkerDrawOptions;
+        MarkerEditor m_Editor;
+
+        IMarker marker { get; }
+
+        bool selectable
+        {
+            get { return m_Selectable; }
+        }
+
+        public double time
+        {
+            get { return marker.time; }
+        }
+
+        public override double start
+        {
+            get { return time; }
+        }
+
+        public override double end
+        {
+            get { return time; }
+        }
+
+        public override void Select()
+        {
+            zOrder = zOrderProvider.Next();
+            SelectionManager.Add(marker);
+            TimelineWindowViewPrefs.GetTrackViewModelData(parent.asset).markerTimeStamps[m_MarkerHash] = DateTime.UtcNow.Ticks;
+        }
+
+        public override bool IsSelected()
+        {
+            return SelectionManager.Contains(marker);
+        }
+
+        public override void Deselect()
+        {
+            SelectionManager.Remove(marker);
+        }
+
+        public override ITimelineItem item
+        {
+            get { return ItemsUtils.ToItem(marker); }
+        }
+
+        IZOrderProvider zOrderProvider { get; }
+
+        public TimelineMarkerGUI(IMarker theMarker, IRowGUI parent, IZOrderProvider provider) : base(parent)
+        {
+            marker = theMarker;
+            m_Selectable = marker.GetType().IsSubclassOf(typeof(UnityObject));
+
+            m_MarkerHash = 0;
+            var o = marker as object;
+            if (!o.Equals(null))
+                m_MarkerHash = o.GetHashCode();
+
+            zOrderProvider = provider;
+            zOrder = zOrderProvider.Next();
+            ItemToItemGui.Add(marker, this);
+            m_Editor = CustomTimelineEditorCache.GetMarkerEditor(theMarker);
+        }
+
+        int ComputeDirtyHash()
+        {
+            return time.GetHashCode();
+        }
+
+        static void DrawMarker(Rect drawRect, Type type, bool isSelected, bool isCollapsed, MarkerDrawOptions options)
+        {
+            if (Event.current.type == EventType.Repaint)
+            {
+                bool hasError = !string.IsNullOrEmpty(options.errorText);
+
+                var style = StyleManager.UssStyleForType(type);
+                style.Draw(drawRect, GUIContent.none, false, false, !isCollapsed, isSelected);
+
+                // case1141836: Use of GUI.Box instead of GUI.Label causes desync in UI controlID
+                if (hasError)
+                    GUI.Label(drawRect, String.Empty, DirectorStyles.Instance.markerWarning);
+
+                var tooltip = hasError ? options.errorText : options.tooltip;
+                if (!string.IsNullOrEmpty(tooltip) && drawRect.Contains(Event.current.mousePosition))
+                {
+                    GUIStyle.SetMouseTooltip(tooltip, drawRect);
+                }
+            }
+        }
+
+        void UpdateDrawData()
+        {
+            if (Event.current.type == EventType.Layout)
+            {
+                try
+                {
+                    m_MarkerDrawOptions = m_Editor.GetMarkerOptions(marker);
+                }
+                catch (Exception e)
+                {
+                    Debug.LogException(e);
+                    m_MarkerDrawOptions = CustomTimelineEditorCache.GetDefaultMarkerEditor().GetMarkerOptions(marker);
+                }
+            }
+        }
+
+        public override void Draw(Rect trackRect, bool trackRectChanged, WindowState state)
+        {
+            UpdateDrawData();
+
+            // compute marker hash
+            var currentMarkerHash = ComputeDirtyHash();
+
+            // update the clip projected rectangle on the timeline
+            CalculateClipRectangle(trackRect, state, currentMarkerHash, trackRectChanged);
+
+            var isSelected = selectable && SelectionManager.Contains(marker);
+            var showMarkers = parent.showMarkers;
+
+            QueueOverlay(treeViewRect, isSelected, !showMarkers);
+            DrawMarker(treeViewRect, marker.GetType(), isSelected, !showMarkers, m_MarkerDrawOptions);
+
+            if (Event.current.type == EventType.Repaint && showMarkers && !parent.locked)
+                state.spacePartitioner.AddBounds(this, rect);
+        }
+
+        public void QueueOverlay(Rect rect, bool isSelected, bool isCollapsed)
+        {
+            if (Event.current.type == EventType.Repaint && m_Editor.supportsDrawOverlay)
+            {
+                rect = GUIClip.Unclip(rect);
+                TimelineWindow.instance.AddUserOverlay(marker, rect, m_Editor, isCollapsed, isSelected);
+            }
+        }
+
+        public override void StartDrag()
+        {
+            if (onStartDrag != null)
+                onStartDrag.Invoke();
+        }
+
+        void CalculateClipRectangle(Rect trackRect, WindowState state, int projectedClipHash, bool trackRectChanged)
+        {
+            if (m_ProjectedClipHash == projectedClipHash && !trackRectChanged)
+                return;
+
+            m_ProjectedClipHash = projectedClipHash;
+            treeViewRect = RectToTimeline(trackRect, state);
+        }
+
+        public override Rect RectToTimeline(Rect trackRect, WindowState state)
+        {
+            var style = StyleManager.UssStyleForType(marker.GetType());
+            var width = style.fixedWidth;
+            var height = style.fixedHeight;
+            var x = ((float)marker.time * state.timeAreaScale.x) + state.timeAreaTranslation.x + trackRect.xMin;
+            x -= 0.5f * width;
+            return new Rect(x, trackRect.y, width, height);
+        }
+
+        public IEnumerable<Edge> SnappableEdgesFor(IAttractable attractable, ManipulateEdges manipulateEdges)
+        {
+            var edges = new List<Edge>();
+            var attractableGUI = attractable as TimelineMarkerGUI;
+            var canAddEdges = !(attractableGUI != null && attractableGUI.parent == parent);
+            if (canAddEdges)
+                edges.Add(new Edge(time));
+            return edges;
+        }
+
+        public bool ShouldSnapTo(ISnappable snappable)
+        {
+            return snappable != this;
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui/TimelineMarkerGUI.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui/TimelineMarkerGUI.cs.meta
new file mode 100644
index 0000000..ecfff45
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ItemGui/TimelineMarkerGUI.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 8d34348f8b97a334291f5cf31adc5d67
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ManipulationsClips.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ManipulationsClips.cs
new file mode 100644
index 0000000..9a51bc6
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ManipulationsClips.cs
@@ -0,0 +1,77 @@
+using System.Linq;
+using UnityEngine;
+using UnityEngine.Timeline;
+
+namespace UnityEditor.Timeline
+{
+    class ItemActionShortcutManipulator : Manipulator
+    {
+        protected override bool ExecuteCommand(Event evt, WindowState state)
+        {
+            if (state.IsEditingASubItem())
+                return false;
+
+            var consumed = false;
+            var clips = SelectionManager.SelectedClips();
+            foreach (var clip in clips)
+                consumed |= ItemAction<TimelineClip>.HandleShortcut(state, evt, clip);
+
+            var markers = SelectionManager.SelectedMarkers();
+            foreach (var marker in markers)
+                consumed |= ItemAction<IMarker>.HandleShortcut(state, evt, marker);
+
+            return consumed;
+        }
+    }
+
+    class DrillIntoClip : Manipulator
+    {
+        protected override bool DoubleClick(Event evt, WindowState state)
+        {
+            if (evt.button != 0)
+                return false;
+
+            var guiClip = PickerUtils.PickedLayerableOfType<TimelineClipGUI>();
+
+            if (guiClip == null)
+                return false;
+
+            if (!TimelineWindow.instance.state.editSequence.isReadOnly && (guiClip.clip.curves != null || guiClip.clip.animationClip != null))
+                ItemAction<TimelineClip>.Invoke<EditClipInAnimationWindow>(state, guiClip.clip);
+
+            if (guiClip.supportsSubTimelines)
+                ItemAction<TimelineClip>.Invoke<EditSubTimeline>(state, guiClip.clip);
+
+            return true;
+        }
+    }
+
+    class ContextMenuManipulator : Manipulator
+    {
+        protected override bool MouseDown(Event evt, WindowState state)
+        {
+            if (evt.button == 1)
+                ItemSelection.HandleSingleSelection(evt);
+
+            return false;
+        }
+
+        protected override bool ContextClick(Event evt, WindowState state)
+        {
+            if (evt.alt)
+                return false;
+
+            var selectable = PickerUtils.PickedLayerableOfType<ISelectable>();
+
+            if (selectable != null && selectable.IsSelected())
+            {
+                SequencerContextMenu.ShowItemContextMenu(evt.mousePosition,
+                    SelectionManager.SelectedClips().ToArray(),
+                    SelectionManager.SelectedMarkers().ToArray());
+                return true;
+            }
+
+            return false;
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ManipulationsClips.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ManipulationsClips.cs.meta
new file mode 100644
index 0000000..c230e78
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ManipulationsClips.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: b222f61a1f7253e4d8e8cc82bfde9e42
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ManipulationsTimeline.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ManipulationsTimeline.cs
new file mode 100644
index 0000000..a3fcac8
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ManipulationsTimeline.cs
@@ -0,0 +1,287 @@
+using System;
+using System.Linq;
+using UnityEditor.ShortcutManagement;
+using UnityEngine;
+
+namespace UnityEditor.Timeline
+{
+    class TimelinePanManipulator : Manipulator
+    {
+        const float k_MaxPanSpeed = 50.0f;
+        bool m_Active;
+
+        protected override bool MouseDown(Event evt, WindowState state)
+        {
+            if ((evt.button == 2 && evt.modifiers == EventModifiers.None) ||
+                (evt.button == 0 && evt.modifiers == EventModifiers.Alt))
+            {
+                TimelineCursors.SetCursor(TimelineCursors.CursorType.Pan);
+
+                m_Active = true;
+                return true;
+            }
+
+            return false;
+        }
+
+        protected override bool MouseUp(Event evt, WindowState state)
+        {
+            if (m_Active)
+            {
+                TimelineCursors.ClearCursor();
+                state.editorWindow.Repaint();
+            }
+
+            return false;
+        }
+
+        protected override bool MouseDrag(Event evt, WindowState state)
+        {
+            // Note: Do not rely on evt.button here as some 3rd party automation
+            //       software does not properly set the button data during drag.
+
+            if (!m_Active)
+                return false;
+
+            return Pan(evt, state);
+        }
+
+        protected override bool MouseWheel(Event evt, WindowState state)
+        {
+            if (Math.Abs(evt.delta.x) < 1e-5 || Math.Abs(evt.delta.x) <= Math.Abs(evt.delta.y))
+                return false;
+
+            TimelineZoomManipulator.InvalidateWheelZoom();
+
+            var panEvent = new Event(evt);
+            panEvent.delta = new Vector2(panEvent.delta.x * k_MaxPanSpeed * -1.0f, 0.0f);
+
+            return Pan(panEvent, state);
+        }
+
+        static bool Pan(Event evt, WindowState state)
+        {
+            var cursorRect = TimelineWindow.instance.sequenceContentRect;
+            cursorRect.xMax = TimelineWindow.instance.position.xMax;
+            cursorRect.yMax = TimelineWindow.instance.position.yMax;
+
+            if (state.GetWindow() != null && state.GetWindow().treeView != null)
+            {
+                var scroll = state.GetWindow().treeView.scrollPosition;
+                scroll.y -= evt.delta.y;
+                state.GetWindow().treeView.scrollPosition = scroll;
+                state.OffsetTimeArea((int)evt.delta.x);
+                return true;
+            }
+
+            return false;
+        }
+    }
+
+
+    class TimelineZoomManipulator : Manipulator
+    {
+        Vector2 m_MouseDownPos = Vector2.zero;
+        Vector2 m_InitialShownRange = Vector2.zero;
+        float m_FocalTime;
+        float m_LastMouseMoveX = -1;
+        float m_ZoomFactor = 1;
+        bool m_WheelUsedLast;
+
+        TimelineZoomManipulator() {}
+
+        public static readonly TimelineZoomManipulator Instance = new TimelineZoomManipulator();
+
+        internal void DoZoom(float zoomFactor, WindowState state)
+        {
+            var refRange = state.timeAreaShownRange;
+            DoZoom(zoomFactor, state, refRange, (refRange.x + refRange.y) / 2);
+            // Force resetting the reference zoom after a Framing operation
+            InvalidateWheelZoom();
+        }
+
+        static void DoZoom(float zoomFactor, WindowState state, Vector2 refRange, float focalTime)
+        {
+            const float kMinRange = 0.05f; // matches zoomable area.
+
+            var s = zoomFactor;
+            if (s <= 0) return;
+
+            var t = Mathf.Max(focalTime, refRange.x);
+            var x = (refRange.x + t * (s - 1)) / s;
+            var y = (refRange.y + t * (s - 1)) / s;
+
+            // don't set it if we reach the limit or panning happens
+            if (Math.Abs(x - y) > kMinRange)
+            {
+                // Zoomable area does not protect 100% against crazy values
+                state.SetTimeAreaShownRange(
+                    Math.Max(x, -WindowConstants.timeAreaShownRangePadding),
+                    Math.Min(y, WindowState.kMaxShownTime));
+            }
+        }
+
+        internal static void InvalidateWheelZoom()
+        {
+            Instance.m_WheelUsedLast = false;
+        }
+
+        protected override bool MouseDown(Event evt, WindowState state)
+        {
+            m_MouseDownPos = evt.mousePosition;
+            m_FocalTime = state.PixelToTime(m_MouseDownPos.x);
+            m_InitialShownRange = state.timeAreaShownRange;
+            return false;
+        }
+
+        protected override bool MouseWheel(Event evt, WindowState state)
+        {
+            if (Math.Abs(evt.delta.y) < 1e-5)
+                return false;
+
+            var zoomRect = TimelineWindow.instance.sequenceContentRect;
+            zoomRect.yMax += TimelineWindow.instance.horizontalScrollbarHeight;
+
+            if (!zoomRect.Contains(evt.mousePosition))
+                return false;
+
+            if (!m_WheelUsedLast || Mathf.Abs(m_LastMouseMoveX - evt.mousePosition.x) > 1.0f)
+            {
+                m_LastMouseMoveX = evt.mousePosition.x;
+                m_FocalTime = state.PixelToTime(m_LastMouseMoveX);
+                m_InitialShownRange = state.timeAreaShownRange;
+                m_ZoomFactor = 1;
+            }
+
+            var newZoom = m_ZoomFactor * (-evt.delta.y * 0.02f + 1);
+            newZoom = Mathf.Clamp(newZoom, 1e-7f, 1e7f);
+
+            var lastRange = state.timeAreaShownRange;
+            DoZoom(newZoom, state, m_InitialShownRange, m_FocalTime);
+
+            // if we hit a limit, don't change the zoom
+            //  this prevents accumulating when zoom doesn't change
+            if (lastRange != state.timeAreaShownRange)
+                m_ZoomFactor = newZoom;
+
+            m_WheelUsedLast = true;
+            return true;
+        }
+
+        protected override bool MouseDrag(Event evt, WindowState state)
+        {
+            // Fast zoom...
+            if (evt.modifiers != EventModifiers.Alt || evt.button != 1) return false;
+
+            var mouseMoveLength = Event.current.mousePosition - m_MouseDownPos;
+            var delta = Math.Abs(mouseMoveLength.x) > Math.Abs(mouseMoveLength.y)
+                ? mouseMoveLength.x
+                : -mouseMoveLength.y;
+            m_ZoomFactor = PixelToZoom(delta);
+            DoZoom(m_ZoomFactor, state, m_InitialShownRange, m_FocalTime);
+
+            m_WheelUsedLast = false;
+            return true;
+        }
+
+        static float PixelToZoom(float x)
+        {
+            const float pixel2Zoom = 1 / 300.0f;
+            x *=  pixel2Zoom;
+            if (x < -0.75)
+            {
+                // Rational function that behaves like 1+x on [-0.75,inf) and asymptotically reaches zero on (-inf,-0.75]
+                // The coefficients were obtained by the following constraints:
+                //1) f(-0.75) = 0.25
+                //2) f'(-0.75) = 1 C1 continuity
+                //3) f(-3) = 0.001 (asymptotically zero)
+                return 1 / (98.6667f + 268.444f * x + 189.63f * x * x);
+            }
+            return 1 + x;
+        }
+    }
+
+    class TimelineShortcutManipulator : Manipulator
+    {
+        protected override bool ValidateCommand(Event evt, WindowState state)
+        {
+            return evt.commandName == EventCommandNames.Copy ||
+                evt.commandName == EventCommandNames.Paste ||
+                evt.commandName == EventCommandNames.Duplicate ||
+                evt.commandName == EventCommandNames.SelectAll ||
+                evt.commandName == EventCommandNames.Delete ||
+                evt.commandName == EventCommandNames.SoftDelete ||
+                evt.commandName == EventCommandNames.FrameSelected;
+        }
+
+        protected override bool ExecuteCommand(Event evt, WindowState state)
+        {
+            if (state.IsCurrentEditingASequencerTextField())
+                return false;
+
+            if (evt.commandName == EventCommandNames.SelectAll)
+            {
+                TimelineAction.Invoke<SelectAllAction>(state);
+                return true;
+            }
+
+            if (evt.commandName == EventCommandNames.SoftDelete)
+            {
+                TimelineAction.Invoke<DeleteAction>(state);
+                return true;
+            }
+
+            if (evt.commandName == EventCommandNames.FrameSelected)
+            {
+                TimelineAction.Invoke<FrameSelectedAction>(state);
+                return true;
+            }
+
+            return TimelineAction.HandleShortcut(state, evt);
+        }
+    }
+
+    class InlineCurvesShortcutManipulator : Manipulator
+    {
+        protected override bool ExecuteCommand(Event evt, WindowState state)
+        {
+            if (state.IsCurrentEditingASequencerTextField())
+                return false;
+
+            var inlineCurveEditor = SelectionManager.GetCurrentInlineEditorCurve();
+            if (inlineCurveEditor == null || !inlineCurveEditor.inlineCurvesSelected)
+                return false;
+
+            if (evt.commandName != EventCommandNames.FrameSelected)
+                return false;
+
+            TimelineAction.Invoke<FrameSelectedAction>(state);
+            return true;
+        }
+
+        // CurveEditor uses an hardcoded shortcut to execute the FrameAll action, preventing the ShortcutManager from
+        // ever picking it up. We have to hijack it to ensure our code is being run when framing inline curves.
+        protected override bool KeyDown(Event evt, WindowState state)
+        {
+            var inlineCurveEditor = SelectionManager.GetCurrentInlineEditorCurve();
+            if (inlineCurveEditor == null || !inlineCurveEditor.inlineCurvesSelected)
+                return false;
+
+            // Not conflicting with the hardcoded value
+            if (evt.keyCode != KeyCode.A)
+                return false;
+
+            var combination = ShortcutManager.instance.GetShortcutBinding(Shortcuts.Timeline.frameAll)
+                .keyCombinationSequence.ToList();
+
+            var shortcutCombination = combination.First();
+            var currentCombination = KeyCombination.FromKeyboardInput(evt);
+
+            // User is not actually pressing the correct key combination for FrameAll
+            if (combination.Count == 1 && shortcutCombination.Equals(currentCombination))
+                TimelineAction.Invoke<FrameAllAction>(state);
+
+            return true;
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ManipulationsTimeline.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ManipulationsTimeline.cs.meta
new file mode 100644
index 0000000..5612ca4
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ManipulationsTimeline.cs.meta
@@ -0,0 +1,11 @@
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+guid: d029640460cf8ff47bbbfe69f49ddf29
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
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+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ManipulationsTracks.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ManipulationsTracks.cs
new file mode 100644
index 0000000..3bd2a1c
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ManipulationsTracks.cs
@@ -0,0 +1,103 @@
+using System.Linq;
+using UnityEngine;
+using UnityEngine.Timeline;
+
+namespace UnityEditor.Timeline
+{
+    class InlineCurveResize : Manipulator
+    {
+        bool m_Captured;
+
+        float m_CapturedHeight;
+        float m_CaptureMouseYPos;
+
+        InlineCurveResizeHandle m_Target;
+
+        protected override bool MouseDown(Event evt, WindowState state)
+        {
+            m_Target = PickerUtils.PickedInlineCurveResizer();
+            if (m_Target == null)
+                return false;
+
+            m_Captured = true;
+            m_CapturedHeight = TimelineWindowViewPrefs.GetInlineCurveHeight(m_Target.trackGUI.track);
+            m_CaptureMouseYPos = GUIUtility.GUIToScreenPoint(Event.current.mousePosition).y;
+            state.AddCaptured(this);
+
+            return true;
+        }
+
+        protected override bool MouseDrag(Event evt, WindowState state)
+        {
+            if (!m_Captured || m_Target == null)
+                return false;
+
+            var trackGUI = m_Target.trackGUI;
+
+            float inlineTrackHeight = m_CapturedHeight +
+                (GUIUtility.GUIToScreenPoint(Event.current.mousePosition).y - m_CaptureMouseYPos);
+
+            TimelineWindowViewPrefs.SetInlineCurveHeight(trackGUI.track, Mathf.Max(inlineTrackHeight, 60.0f));
+
+            state.GetWindow().treeView.CalculateRowRects();
+
+            return true;
+        }
+
+        protected override bool MouseUp(Event evt, WindowState state)
+        {
+            if (!m_Captured)
+                return false;
+
+            state.RemoveCaptured(this);
+            m_Captured = false;
+
+            return true;
+        }
+    }
+
+    class TrackDoubleClick : Manipulator
+    {
+        protected override bool DoubleClick(Event evt, WindowState state)
+        {
+            if (evt.button != 0)
+                return false;
+
+            var trackGUI = PickerUtils.PickedTrackBaseGUI();
+
+            if (trackGUI == null)
+                return false;
+
+            // Double-click is only available for AnimationTracks: it conflicts with selection mechanics on other tracks
+            if ((trackGUI.track as AnimationTrack) == null)
+                return false;
+
+            return EditTrackInAnimationWindow.Do(state, trackGUI.track);
+        }
+    }
+
+    class TrackShortcutManipulator : Manipulator
+    {
+        protected override bool ExecuteCommand(Event evt, WindowState state)
+        {
+            if (state.IsCurrentEditingASequencerTextField())
+                return false;
+
+            var tracks = SelectionManager.SelectedTracks().ToList();
+
+            var itemGUIs = SelectionManager.SelectedClipGUI();
+
+            foreach (var itemGUI in itemGUIs)
+            {
+                var trackGUI = itemGUI.parent == null ? null : itemGUI.parent as TimelineTrackBaseGUI;
+                if (trackGUI == null)
+                    continue;
+
+                if (!tracks.Contains(trackGUI.track))
+                    tracks.Add(trackGUI.track);
+            }
+
+            return TrackAction.HandleShortcut(state, evt, tracks.ToArray());
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ManipulationsTracks.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ManipulationsTracks.cs.meta
new file mode 100644
index 0000000..cfbbb31
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/ManipulationsTracks.cs.meta
@@ -0,0 +1,11 @@
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diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Manipulator.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Manipulator.cs
new file mode 100644
index 0000000..d0aac15
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Manipulator.cs
@@ -0,0 +1,91 @@
+using UnityEngine;
+
+namespace UnityEditor.Timeline
+{
+    abstract class Manipulator
+    {
+        int m_Id;
+
+        protected virtual bool MouseDown(Event evt, WindowState state) { return false; }
+        protected virtual bool MouseDrag(Event evt, WindowState state) { return false; }
+        protected virtual bool MouseWheel(Event evt, WindowState state) { return false; }
+        protected virtual bool MouseUp(Event evt, WindowState state) { return false; }
+        protected virtual bool DoubleClick(Event evt, WindowState state) { return false; }
+        protected virtual bool KeyDown(Event evt, WindowState state) { return false; }
+        protected virtual bool KeyUp(Event evt, WindowState state) { return false; }
+        protected virtual bool ContextClick(Event evt, WindowState state) { return false; }
+        protected virtual bool ValidateCommand(Event evt, WindowState state) { return false; }
+        protected virtual bool ExecuteCommand(Event evt, WindowState state) { return false; }
+
+        public virtual void Overlay(Event evt, WindowState state) {}
+
+        public bool HandleEvent(WindowState state)
+        {
+            if (m_Id == 0)
+                m_Id =  GUIUtility.GetPermanentControlID();
+
+            bool isHandled = false;
+            var evt = Event.current;
+
+            switch (evt.GetTypeForControl(m_Id))
+            {
+                case EventType.ScrollWheel:
+                    isHandled = MouseWheel(evt, state);
+                    break;
+
+                case EventType.MouseUp:
+                {
+                    if (GUIUtility.hotControl == m_Id)
+                    {
+                        isHandled = MouseUp(evt, state);
+
+                        GUIUtility.hotControl = 0;
+                        evt.Use();
+                    }
+                }
+                break;
+
+                case EventType.MouseDown:
+                {
+                    isHandled = evt.clickCount < 2 ? MouseDown(evt, state) : DoubleClick(evt, state);
+
+                    if (isHandled)
+                        GUIUtility.hotControl = m_Id;
+                }
+                break;
+
+                case EventType.MouseDrag:
+                {
+                    if (GUIUtility.hotControl == m_Id)
+                        isHandled = MouseDrag(evt, state);
+                }
+                break;
+
+                case EventType.KeyDown:
+                    isHandled = KeyDown(evt, state);
+                    break;
+
+                case EventType.KeyUp:
+                    isHandled = KeyUp(evt, state);
+                    break;
+
+                case EventType.ContextClick:
+                    isHandled = ContextClick(evt, state);
+                    break;
+
+                case EventType.ValidateCommand:
+                    isHandled = ValidateCommand(evt, state);
+                    break;
+
+                case EventType.ExecuteCommand:
+                    isHandled = ExecuteCommand(evt, state);
+                    break;
+            }
+
+            if (isHandled)
+                evt.Use();
+
+            return isHandled;
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Manipulator.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Manipulator.cs.meta
new file mode 100644
index 0000000..9676bc0
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Manipulator.cs.meta
@@ -0,0 +1,11 @@
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+guid: 2bf68308f6cdff141ab98cd34174e4f1
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diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/PickerUtils.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/PickerUtils.cs
new file mode 100644
index 0000000..50d0382
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/PickerUtils.cs
@@ -0,0 +1,41 @@
+using System.Collections.Generic;
+using System.Linq;
+using UnityEngine;
+
+namespace UnityEditor.Timeline
+{
+    static class PickerUtils
+    {
+        public static List<object> pickedElements { get; private set; }
+
+        public static void DoPick(WindowState state, Vector2 mousePosition)
+        {
+            if (state.GetWindow().sequenceContentRect.Contains(mousePosition))
+            {
+                pickedElements = state.spacePartitioner.GetItemsAtPosition<object>(mousePosition).ToList();
+            }
+            else
+            {
+                if (pickedElements != null)
+                    pickedElements.Clear();
+                else
+                    pickedElements = new List<object>();
+            }
+        }
+
+        public static T PickedLayerableOfType<T>() where T : class, ILayerable
+        {
+            return pickedElements.OfType<ILayerable>().OrderBy(x => x.zOrder).LastOrDefault() as T;
+        }
+
+        public static InlineCurveResizeHandle PickedInlineCurveResizer()
+        {
+            return pickedElements.FirstOrDefault(e => e is InlineCurveResizeHandle) as InlineCurveResizeHandle;
+        }
+
+        public static TimelineTrackBaseGUI PickedTrackBaseGUI()
+        {
+            return pickedElements.FirstOrDefault(e => e is TimelineTrackBaseGUI) as TimelineTrackBaseGUI;
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/PickerUtils.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/PickerUtils.cs.meta
new file mode 100644
index 0000000..829ef0a
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/PickerUtils.cs.meta
@@ -0,0 +1,11 @@
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diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Snapping.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Snapping.meta
new file mode 100644
index 0000000..bb822d5
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Snapping.meta
@@ -0,0 +1,8 @@
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+guid: 06ae1baf5524b314fa65b173b9eca869
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+  externalObjects: {}
+  userData: 
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diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Snapping/IAttractable.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Snapping/IAttractable.cs
new file mode 100644
index 0000000..772809d
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Snapping/IAttractable.cs
@@ -0,0 +1,21 @@
+namespace UnityEditor.Timeline
+{
+    enum AttractedEdge
+    {
+        None,
+        Left,
+        Right
+    }
+
+    interface IAttractable
+    {
+        bool ShouldSnapTo(ISnappable snappable);
+        double start { get; }
+        double end { get; }
+    }
+
+    interface IAttractionHandler
+    {
+        void OnAttractedEdge(IAttractable attractable, ManipulateEdges manipulateEdges, AttractedEdge edge, double time);
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Snapping/IAttractable.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Snapping/IAttractable.cs.meta
new file mode 100644
index 0000000..570a8b9
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Snapping/IAttractable.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 6bfec54ce89b0b642a65d44def023b99
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Snapping/ISnappable.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Snapping/ISnappable.cs
new file mode 100644
index 0000000..52a17a6
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Snapping/ISnappable.cs
@@ -0,0 +1,22 @@
+using System.Collections.Generic;
+
+namespace UnityEditor.Timeline
+{
+    struct Edge
+    {
+        public double time { get; set; }
+
+        public bool showSnapHint { get; set; }
+
+        public Edge(double edgeTime, bool snapHint = true) : this()
+        {
+            time = edgeTime;
+            showSnapHint = snapHint;
+        }
+    }
+
+    interface ISnappable
+    {
+        IEnumerable<Edge> SnappableEdgesFor(IAttractable attractable, ManipulateEdges manipulateEdges);
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Snapping/ISnappable.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Snapping/ISnappable.cs.meta
new file mode 100644
index 0000000..dccc3e2
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Snapping/ISnappable.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 3664a2ade19bb7848a4d2c96ac9148e3
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Snapping/SnapEngine.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Snapping/SnapEngine.cs
new file mode 100644
index 0000000..8aca3d4
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Snapping/SnapEngine.cs
@@ -0,0 +1,288 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using UnityEngine;
+using UnityEngine.Timeline;
+
+namespace UnityEditor.Timeline
+{
+    enum ManipulateEdges
+    {
+        Left,
+        Right,
+        Both
+    }
+
+    class SnapEngine
+    {
+        static readonly float k_MagnetInfluenceInPixels = 10.0f;
+
+        class SnapInfo
+        {
+            public double time { get; set; }
+
+            public bool showSnapHint { get; set; }
+
+            public bool IsInInfluenceZone(double currentTime, WindowState state)
+            {
+                var pos = state.TimeToPixel(currentTime);
+                var magnetPos = state.TimeToPixel(time);
+
+                return Math.Abs(pos - magnetPos) < k_MagnetInfluenceInPixels;
+            }
+        }
+
+        struct TimeBoundaries
+        {
+            public TimeBoundaries(double l, double r)
+            {
+                left = l;
+                right = r;
+            }
+
+            public readonly double left;
+            public readonly double right;
+
+            public TimeBoundaries Translate(double d)
+            {
+                return new TimeBoundaries(left + d, right + d);
+            }
+        }
+
+        public static bool displayDebugLayout;
+
+        readonly IAttractable m_Attractable;
+        readonly IAttractionHandler m_AttractionHandler;
+        readonly ManipulateEdges m_ManipulateEdges;
+
+        readonly WindowState m_State;
+
+        double m_GrabbedTime;
+        TimeBoundaries m_GrabbedTimes;
+
+        TimeBoundaries m_CurrentTimes;
+
+        readonly List<SnapInfo> m_Magnets = new List<SnapInfo>();
+
+        bool m_SnapEnabled;
+
+        public SnapEngine(IAttractable attractable, IAttractionHandler attractionHandler, ManipulateEdges manipulateEdges, WindowState state,
+                          Vector2 mousePosition, IEnumerable<ISnappable> snappables = null)
+        {
+            m_Attractable = attractable;
+            m_ManipulateEdges = manipulateEdges;
+
+            m_AttractionHandler = attractionHandler;
+            m_State = state;
+
+            m_CurrentTimes = m_GrabbedTimes = new TimeBoundaries(m_Attractable.start, m_Attractable.end);
+            m_GrabbedTime = m_State.PixelToTime(mousePosition.x);
+
+            // Add Time zero as Magnet
+            AddMagnet(0.0, true, state);
+
+            // Add current Time as Magnet
+            // case1157280 only add current time as magnet if visible
+            if (TimelineWindow.instance.currentMode.ShouldShowTimeCursor(m_State))
+                AddMagnet(state.editSequence.time, true, state);
+
+            if (state.IsEditingASubTimeline())
+            {
+                // Add start and end of evaluable range as Magnets
+                // This includes the case where the master timeline has a fixed length
+                var range = state.editSequence.GetEvaluableRange();
+                AddMagnet(range.start, true, state);
+                AddMagnet(range.end, true, state);
+            }
+            else if (state.masterSequence.asset.durationMode == TimelineAsset.DurationMode.FixedLength)
+            {
+                // Add end sequence Time as Magnet
+                AddMagnet(state.masterSequence.asset.duration, true, state);
+            }
+
+
+            if (snappables == null)
+                snappables = GetVisibleSnappables(m_State);
+
+            foreach (var snappable in snappables)
+            {
+                if (!attractable.ShouldSnapTo(snappable))
+                    continue;
+
+                var edges = snappable.SnappableEdgesFor(attractable, manipulateEdges);
+                foreach (var edge in edges)
+                    AddMagnet(edge.time, edge.showSnapHint, state);
+            }
+        }
+
+        public static IEnumerable<ISnappable> GetVisibleSnappables(WindowState state)
+        {
+            Rect rect = TimelineWindow.instance.state.timeAreaRect;
+            rect.height = float.MaxValue;
+            return state.spacePartitioner.GetItemsInArea<ISnappable>(rect).ToArray();
+        }
+
+        void AddMagnet(double magnetTime, bool showSnapHint, WindowState state)
+        {
+            var magnet = m_Magnets.FirstOrDefault(m => m.time.Equals(magnetTime));
+            if (magnet == null)
+            {
+                if (IsMagnetInShownArea(magnetTime, state))
+                    m_Magnets.Add(new SnapInfo { time = magnetTime, showSnapHint = showSnapHint });
+            }
+            else
+            {
+                magnet.showSnapHint |= showSnapHint;
+            }
+        }
+
+        static bool IsMagnetInShownArea(double time, WindowState state)
+        {
+            var shownArea = state.timeAreaShownRange;
+            return time >= shownArea.x && time <= shownArea.y;
+        }
+
+        SnapInfo GetMagnetAt(double time)
+        {
+            return m_Magnets.FirstOrDefault(m => m.time.Equals(time));
+        }
+
+        SnapInfo ClosestMagnet(double time)
+        {
+            SnapInfo candidate = null;
+            var min = double.MaxValue;
+            foreach (var magnetInfo in m_Magnets)
+            {
+                var m = Math.Abs(magnetInfo.time - time);
+                if (m < min)
+                {
+                    candidate = magnetInfo;
+                    min = m;
+                }
+            }
+
+            if (candidate != null && candidate.IsInInfluenceZone(time, m_State))
+                return candidate;
+
+            return null;
+        }
+
+        public void Snap(Vector2 currentMousePosition, EventModifiers modifiers)
+        {
+            var d = m_State.PixelToTime(currentMousePosition.x) - m_GrabbedTime;
+
+            m_CurrentTimes = m_GrabbedTimes.Translate(d);
+
+            bool isLeft = m_ManipulateEdges == ManipulateEdges.Left || m_ManipulateEdges == ManipulateEdges.Both;
+            bool isRight = m_ManipulateEdges == ManipulateEdges.Right || m_ManipulateEdges == ManipulateEdges.Both;
+
+            bool attracted = false;
+
+            m_SnapEnabled = modifiers == ManipulatorsUtils.actionModifier ? !m_State.edgeSnaps : m_State.edgeSnaps;
+
+            if (m_SnapEnabled)
+            {
+                SnapInfo leftActiveMagnet = null;
+                SnapInfo rightActiveMagnet = null;
+
+                if (isLeft)
+                    leftActiveMagnet = ClosestMagnet(m_CurrentTimes.left);
+
+                if (isRight)
+                    rightActiveMagnet = ClosestMagnet(m_CurrentTimes.right);
+
+                if (leftActiveMagnet != null || rightActiveMagnet != null)
+                {
+                    attracted = true;
+
+                    bool leftAttraction = false;
+
+                    if (rightActiveMagnet == null)
+                    {
+                        // Attracted by a left magnet only.
+                        leftAttraction = true;
+                    }
+                    else
+                    {
+                        if (leftActiveMagnet != null)
+                        {
+                            // Attracted by both magnets, choose the closest one.
+                            var leftDistance = Math.Abs(leftActiveMagnet.time - m_CurrentTimes.left);
+                            var rightDistance = Math.Abs(rightActiveMagnet.time - m_CurrentTimes.right);
+
+                            leftAttraction = leftDistance <= rightDistance;
+                        }
+                        // else, Attracted by right magnet only
+                    }
+
+                    if (leftAttraction)
+                    {
+                        m_AttractionHandler.OnAttractedEdge(m_Attractable, m_ManipulateEdges, AttractedEdge.Left, leftActiveMagnet.time);
+                    }
+                    else
+                    {
+                        m_AttractionHandler.OnAttractedEdge(m_Attractable, m_ManipulateEdges, AttractedEdge.Right, rightActiveMagnet.time);
+                    }
+                }
+            }
+
+            if (!attracted)
+            {
+                var time = isLeft ? m_CurrentTimes.left : m_CurrentTimes.right;
+
+                time = m_State.SnapToFrameIfRequired(time);
+
+                m_AttractionHandler.OnAttractedEdge(m_Attractable, m_ManipulateEdges, AttractedEdge.None, time);
+            }
+        }
+
+        public void OnGUI(bool showLeft = true, bool showRight = true)
+        {
+            if (displayDebugLayout)
+            {
+                // Display Magnet influence zone
+                foreach (var m in m_Magnets)
+                {
+                    var window = TimelineWindow.instance;
+                    var rect = new Rect(m_State.TimeToPixel(m.time) - k_MagnetInfluenceInPixels, window.state.timeAreaRect.yMax, 2f * k_MagnetInfluenceInPixels, m_State.windowHeight);
+                    EditorGUI.DrawRect(rect, new Color(1f, 0f, 0f, 0.4f));
+                }
+
+                // Display Cursor position
+                var mousePos = Event.current.mousePosition;
+                var time = m_State.PixelToTime(mousePos.x);
+                var p = new Vector2(m_State.TimeToPixel(time), TimelineWindow.instance.state.timeAreaRect.yMax);
+                var s = new Vector2(1f, m_State.windowHeight);
+                EditorGUI.DrawRect(new Rect(p, s), Color.blue);
+
+                p = new Vector2(m_State.TimeToPixel(m_GrabbedTime), TimelineWindow.instance.state.timeAreaRect.yMax);
+                s = new Vector2(1f, m_State.windowHeight);
+                EditorGUI.DrawRect(new Rect(p, s), Color.red);
+
+                p = new Vector2(m_State.TimeToPixel(m_CurrentTimes.left), TimelineWindow.instance.state.timeAreaRect.yMax);
+                s = new Vector2(1f, m_State.windowHeight);
+                EditorGUI.DrawRect(new Rect(p, s), Color.yellow);
+
+                p = new Vector2(m_State.TimeToPixel(m_CurrentTimes.right), TimelineWindow.instance.state.timeAreaRect.yMax);
+                EditorGUI.DrawRect(new Rect(p, s), Color.yellow);
+            }
+
+            if (m_SnapEnabled)
+            {
+                if (showLeft)
+                    DrawMagnetLineAt(m_Attractable.start);
+
+                if (showRight)
+                    DrawMagnetLineAt(m_Attractable.end);
+            }
+        }
+
+        void DrawMagnetLineAt(double time)
+        {
+            var magnet = GetMagnetAt(time);
+
+            if (magnet != null && magnet.showSnapHint)
+                Graphics.DrawLineAtTime(m_State, magnet.time, Color.white);
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Snapping/SnapEngine.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Snapping/SnapEngine.cs.meta
new file mode 100644
index 0000000..a2ce57d
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/Snapping/SnapEngine.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 48967a2d5427ac2489cc0ea61da5f1a0
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineClipHandle.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineClipHandle.cs
new file mode 100644
index 0000000..6bd2238
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineClipHandle.cs
@@ -0,0 +1,53 @@
+using UnityEngine;
+
+namespace UnityEditor.Timeline
+{
+    class TimelineClipHandle : ILayerable
+    {
+        Rect m_Rect;
+        readonly TimelineClipGUI m_ClipGUI;
+        readonly TrimEdge m_TrimDirection;
+        readonly LayerZOrder m_ZOrder;
+
+        public Rect boundingRect
+        {
+            get { return m_ClipGUI.parent.ToWindowSpace(m_Rect); }
+        }
+
+        public TrimEdge trimDirection
+        {
+            get { return m_TrimDirection; }
+        }
+
+        public TimelineClipGUI clipGUI
+        {
+            get { return m_ClipGUI; }
+        }
+
+        public LayerZOrder zOrder
+        {
+            get { return m_ZOrder; }
+        }
+
+        public TimelineClipHandle(TimelineClipGUI theClipGUI, TrimEdge trimDirection)
+        {
+            m_TrimDirection = trimDirection;
+            m_ClipGUI = theClipGUI;
+            m_ZOrder = theClipGUI.zOrder.ChangeLayer(Layer.ClipHandles);
+        }
+
+        public void Draw(Rect clientRect, float width, WindowState state)
+        {
+            var handleRect = clientRect;
+            handleRect.width = width;
+
+            if (m_TrimDirection == TrimEdge.End)
+                handleRect.x = clientRect.xMax - width;
+
+            m_Rect = handleRect;
+            if (!TimelineWindow.instance.state.editSequence.isReadOnly)
+                EditorGUIUtility.AddCursorRect(handleRect, MouseCursor.SplitResizeLeftRight);
+            state.spacePartitioner.AddBounds(this, boundingRect);
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineClipHandle.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineClipHandle.cs.meta
new file mode 100644
index 0000000..df0e041
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineClipHandle.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 3e29cdd1646803545b8fb18908666ec4
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineClipUnion.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineClipUnion.cs
new file mode 100644
index 0000000..4288992
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineClipUnion.cs
@@ -0,0 +1,126 @@
+using System.Collections.Generic;
+using System.Linq;
+using UnityEditorInternal;
+using UnityEngine;
+
+namespace UnityEditor.Timeline
+{
+    class TimelineClipUnion
+    {
+        List<TimelineClipGUI> m_Members = new List<TimelineClipGUI>();
+        Rect m_BoundingRect;
+        Rect m_Union;
+        double m_Start;
+        double m_Duration;
+        bool m_InitUnionRect = true;
+
+        void Add(TimelineClipGUI clip)
+        {
+            m_Members.Add(clip);
+            if (m_Members.Count == 1)
+            {
+                m_BoundingRect = clip.clippedRect;
+            }
+            else
+            {
+                m_BoundingRect = Encompass(m_BoundingRect, clip.rect);
+            }
+        }
+
+        public void Draw(Rect parentRect, WindowState state)
+        {
+            if (m_InitUnionRect)
+            {
+                m_Start = m_Members.OrderBy(c => c.clip.start).First().clip.start;
+                m_Duration = m_Members.Sum(c => c.clip.duration);
+                m_InitUnionRect = false;
+            }
+
+            m_Union = new Rect((float)(m_Start) * state.timeAreaScale.x, 0, (float)m_Duration * state.timeAreaScale.x, 0);
+
+            // transform clipRect into pixel-space
+            m_Union.xMin += state.timeAreaTranslation.x + parentRect.x;
+            m_Union.xMax += state.timeAreaTranslation.x + parentRect.x;
+            m_Union.y = parentRect.y + 4.0f;
+            m_Union.height = parentRect.height - 8.0f;
+
+            // calculate clipped rect
+            if (m_Union.x < parentRect.xMin)
+            {
+                var overflow = parentRect.xMin - m_Union.x;
+                m_Union.x = parentRect.xMin;
+                m_Union.width -= overflow;
+            }
+
+            // bail out if completely clipped
+            if (m_Union.xMax < parentRect.xMin)
+                return;
+            if (m_Union.xMin > parentRect.xMax)
+                return;
+
+            EditorGUI.DrawRect(m_Union, DirectorStyles.Instance.customSkin.colorClipUnion);
+        }
+
+        public static List<TimelineClipUnion> Build(List<TimelineClipGUI> clips)
+        {
+            var unions = new List<TimelineClipUnion>();
+            if (clips == null)
+                return unions;
+
+            TimelineClipUnion currentUnion = null;
+            foreach (var c in clips)
+            {
+                if (currentUnion == null)
+                {
+                    currentUnion = new TimelineClipUnion();
+                    currentUnion.Add(c);
+                    unions.Add(currentUnion);
+                }
+                else
+                {
+                    Rect result;
+                    if (Intersection(c.rect, currentUnion.m_BoundingRect, out result))
+                    {
+                        currentUnion.Add(c);
+                    }
+                    else
+                    {
+                        currentUnion = new TimelineClipUnion();
+                        currentUnion.Add(c);
+                        unions.Add(currentUnion);
+                    }
+                }
+            }
+
+            return unions;
+        }
+
+        public static Rect Encompass(Rect a, Rect b)
+        {
+            Rect newRect = a;
+            newRect.xMin = Mathf.Min(a.xMin, b.xMin);
+            newRect.yMin = Mathf.Min(a.yMin, b.yMin);
+            newRect.xMax = Mathf.Max(a.xMax, b.xMax);
+            newRect.yMax = Mathf.Max(a.yMax, b.yMax);
+            return newRect;
+        }
+
+        public static bool Intersection(Rect r1, Rect r2, out Rect intersection)
+        {
+            if (!r1.Overlaps(r2) && !r2.Overlaps(r1))
+            {
+                intersection = new Rect(0, 0, 0, 0);
+                return false;
+            }
+
+            float left = Mathf.Max(r1.xMin, r2.xMin);
+            float top = Mathf.Max(r1.yMin, r2.yMin);
+
+            float right = Mathf.Min(r1.xMax, r2.xMax);
+            float bottom = Mathf.Min(r1.yMax, r2.yMax);
+
+            intersection = new Rect(left, top, right - left, bottom - top);
+            return true;
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineClipUnion.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineClipUnion.cs.meta
new file mode 100644
index 0000000..86b5654
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineClipUnion.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: dc99dfeec967f2644b25dd6bace59b7e
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineDataSource.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineDataSource.cs
new file mode 100644
index 0000000..2337392
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineDataSource.cs
@@ -0,0 +1,222 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using UnityEditor.IMGUI.Controls;
+using UnityEngine;
+using UnityEngine.Playables;
+using UnityEngine.Timeline;
+
+namespace UnityEditor.Timeline
+{
+    class TimelineDataSource : TreeViewDataSource
+    {
+        readonly TimelineWindow m_TimelineWindow;
+        readonly TimelineTreeViewGUI m_ParentGUI;
+
+        public List<TimelineTrackBaseGUI> allTrackGuis { get; private set; }
+
+        TreeViewItem treeroot
+        {
+            get { return m_RootItem; }
+        }
+
+        public TimelineDataSource(TimelineTreeViewGUI parentGUI, TreeViewController treeView, TimelineWindow sequencerWindow)
+            : base(treeView)
+        {
+            m_TreeView.useExpansionAnimation = false;
+            m_TimelineWindow = sequencerWindow;
+            m_ParentGUI = parentGUI;
+            FetchData();
+        }
+
+        public override bool IsExpanded(TreeViewItem item)
+        {
+            if (!IsExpandable(item))
+                return true;
+
+            return IsExpanded(item.id);
+        }
+
+        public override bool IsExpandable(TreeViewItem item)
+        {
+            var expandable = false;
+
+            var track = item as TimelineTrackBaseGUI;
+
+            if (track != null)
+                expandable =  track.expandable;
+
+            return expandable && item.hasChildren;
+        }
+
+        public sealed override void FetchData()
+        {
+            // create root item
+            m_RootItem = new TimelineGroupGUI(m_TreeView, m_ParentGUI, 1, 0, null, "root", null, true);
+
+            var tree = new Dictionary<TrackAsset, TimelineTrackBaseGUI>();
+
+            var filteredView = m_TimelineWindow.state.editSequence.asset.trackObjects;
+            allTrackGuis = new List<TimelineTrackBaseGUI>(filteredView.Count());
+
+            foreach (var t in filteredView)
+            {
+                CreateItem(t, ref tree, filteredView.OfType<TrackAsset>(), m_RootItem);
+            }
+
+            m_NeedRefreshRows = true;
+
+            SetExpanded(m_RootItem, true);
+        }
+
+        TimelineTrackBaseGUI CreateItem(ScriptableObject scriptableObject, ref Dictionary<TrackAsset, TimelineTrackBaseGUI> tree, IEnumerable<TrackAsset> selectedRows, TreeViewItem parentTreeViewItem)
+        {
+            // if a script doesn't load correctly, the trackAsset will be NULL, but the scriptableObject __should_ be intact (but == null will be true)
+            var trackAsset = scriptableObject as TrackAsset;
+
+            if (tree == null)
+                throw new ArgumentNullException("tree");
+
+            if (selectedRows == null)
+                throw new ArgumentNullException("selectedRows");
+
+            if (trackAsset != null && tree.ContainsKey(trackAsset))
+                return tree[trackAsset];
+
+            TimelineTrackBaseGUI parentItem = parentTreeViewItem as TimelineTrackBaseGUI;
+
+            // should we create the parent?
+            TrackAsset parentTrack = trackAsset != null ? (trackAsset.parent as TrackAsset) : null;
+            if (trackAsset != null && parentTrack != null && selectedRows.Contains(parentTrack))
+            {
+                parentItem = CreateItem(parentTrack, ref tree, selectedRows, parentTreeViewItem);
+            }
+
+            int theDepth = -1;
+            if (parentItem != null)
+                theDepth = parentItem.depth;
+            theDepth++;
+
+            TimelineTrackBaseGUI newItem;
+            if (trackAsset == null)
+            {
+                PlayableAsset parent = m_TimelineWindow.state.editSequence.asset;
+                if (parentItem != null && parentItem.track != null)
+                    parent = parentItem.track;
+
+                newItem = new TimelineTrackErrorGUI(m_TreeView, m_ParentGUI, 0, theDepth, parentItem, "ERROR", scriptableObject, parent);
+            }
+            else if (trackAsset.GetType() != typeof(GroupTrack))
+            {
+                newItem = new TimelineTrackGUI(m_TreeView, m_ParentGUI, trackAsset.GetInstanceID(), theDepth, parentItem, trackAsset.name, trackAsset);
+            }
+            else
+            {
+                newItem = new TimelineGroupGUI(m_TreeView, m_ParentGUI, trackAsset.GetInstanceID(), theDepth, parentItem, trackAsset.name, trackAsset, false);
+            }
+
+            allTrackGuis.Add(newItem);
+
+            if (parentItem != null)
+            {
+                if (parentItem.children == null)
+                    parentItem.children = new List<TreeViewItem>();
+                parentItem.children.Add(newItem);
+            }
+            else
+            {
+                m_RootItem = newItem;
+                SetExpanded(m_RootItem, true);
+            }
+
+            if (trackAsset != null)
+                tree[trackAsset] = newItem;
+
+            var actorAsAnimTrack = newItem.track as AnimationTrack;
+            bool isEditableInfiniteClip = actorAsAnimTrack != null && actorAsAnimTrack.ShouldShowInfiniteClipEditor();
+            if (isEditableInfiniteClip)
+            {
+                if (newItem.children == null)
+                    newItem.children = new List<TreeViewItem>();
+            }
+            else if (trackAsset != null)
+            {
+                // check if clips on this track have animation, if so we inline a animationEditorTrack
+                bool clipHasAnimatableAnimationCurves = false;
+
+                for (var i = 0; i != newItem.track.clips.Length; ++i)
+                {
+                    var curveClip = newItem.track.clips[i].curves;
+                    var animationClip = newItem.track.clips[i].animationClip;
+
+                    // prune out clip with zero curves
+                    if (curveClip != null && curveClip.empty)
+                        curveClip = null;
+
+                    if (animationClip != null && animationClip.empty)
+                        animationClip = null;
+
+                    // prune out clips coming from FBX
+                    if (animationClip != null && ((animationClip.hideFlags & HideFlags.NotEditable) != 0))
+                        animationClip = null;
+
+                    if (!newItem.track.clips[i].recordable)
+                        animationClip = null;
+
+                    clipHasAnimatableAnimationCurves = (curveClip != null) || (animationClip != null);
+                    if (clipHasAnimatableAnimationCurves)
+                        break;
+                }
+
+                if (clipHasAnimatableAnimationCurves)
+                {
+                    if (newItem.children == null)
+                        newItem.children = new List<TreeViewItem>();
+                }
+            }
+
+            if (trackAsset != null)
+            {
+                // Here we are using the internal subTrackObject so we can properly handle tracks whose script
+                //  can't load (via ScriptableObject)
+                foreach (var subTrack in trackAsset.subTracksObjects)
+                {
+                    CreateItem(subTrack, ref tree, selectedRows, newItem);
+                }
+            }
+            return newItem;
+        }
+
+        public override bool CanBeParent(TreeViewItem item)
+        {
+            // will prevent track becoming subtracks via dragging
+            TimelineTrackGUI track = item as TimelineTrackGUI;
+            if (track != null)
+                return false;
+
+            return true;
+        }
+
+        public void ExpandItems(TreeViewItem item)
+        {
+            if (treeroot == item)
+            {
+                SetExpanded(treeroot, true);
+            }
+
+            TimelineGroupGUI gui = item as TimelineGroupGUI;
+            if (gui != null && gui.track != null)
+            {
+                SetExpanded(item, !gui.track.GetCollapsed());
+            }
+
+            if (item.children != null)
+            {
+                for (int c = 0; c < item.children.Count; c++)
+                {
+                    ExpandItems(item.children[c]);
+                }
+            }
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineDataSource.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineDataSource.cs.meta
new file mode 100644
index 0000000..5d40d2d
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineDataSource.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: e8c30efa89029e447b0dc0efc75b294c
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineDragging.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineDragging.cs
new file mode 100644
index 0000000..8162c06
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineDragging.cs
@@ -0,0 +1,683 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using UnityEditor.IMGUI.Controls;
+using UnityEditor.Timeline;
+using UnityEngine;
+using UnityEngine.Timeline;
+using UnityEngine.Playables;
+using UnityObject = UnityEngine.Object;
+
+namespace UnityEditor
+{
+    class TimelineDragging : TreeViewDragging
+    {
+        public delegate bool TypeResolver(IEnumerable<Type> types, Action<Type> onComplete, string format);
+
+        private static readonly string k_SelectTrackWithBinding = LocalizationDatabase.GetLocalizedString("Add {0}");
+        private static readonly string k_SelectTrackWithClip = LocalizationDatabase.GetLocalizedString("Add Clip With {0}");
+        private static readonly string k_SelectClip = LocalizationDatabase.GetLocalizedString("Add {0}");
+
+
+        const string k_GenericDragId = "TimelineDragging";
+        readonly int kDragSensitivity = 2;
+        readonly TimelineAsset m_Timeline;
+        readonly TimelineWindow m_Window;
+
+        class TimelineDragData
+        {
+            public TimelineDragData(List<TreeViewItem> draggedItems)
+            {
+                this.draggedItems = draggedItems;
+            }
+
+            public readonly List<TreeViewItem> draggedItems;
+        }
+
+        public TimelineDragging(TreeViewController treeView, TimelineWindow window, TimelineAsset data)
+            : base(treeView)
+        {
+            m_Timeline = data;
+            m_Window = window;
+        }
+
+        public override bool CanStartDrag(TreeViewItem targetItem, List<int> draggedItemIDs, Vector2 mouseDownPosition)
+        {
+            if (Event.current.modifiers != EventModifiers.None)
+                return false;
+
+            // Can only drag when starting in the track header area
+            if (mouseDownPosition.x > m_Window.sequenceHeaderRect.xMax)
+                return false;
+
+            var trackBaseGUI = targetItem as TimelineTrackBaseGUI;
+
+            if (trackBaseGUI == null || trackBaseGUI.track == null)
+                return false;
+
+            if (trackBaseGUI.track.lockedInHierarchy)
+                return false;
+
+            if (Event.current.type == EventType.MouseDrag && Mathf.Abs(Event.current.delta.y) < kDragSensitivity)
+                return false;
+
+            // Make sure dragged items are selected
+            // TODO Use similar system than the SceneHierarchyWindow in order to handle selection between treeView and tracks.
+            SelectionManager.Clear();
+            var draggedTrackGUIs = m_Window.allTracks.Where(t => draggedItemIDs.Contains(t.id));
+            foreach (var trackGUI in draggedTrackGUIs)
+                SelectionManager.Add(trackGUI.track);
+
+            return true;
+        }
+
+        public override void StartDrag(TreeViewItem draggedNode, List<int> draggedItemIDs)
+        {
+            DragAndDrop.PrepareStartDrag();
+            var tvItems = SelectionManager.SelectedTrackGUI().Cast<TreeViewItem>().ToList();
+            DragAndDrop.SetGenericData(k_GenericDragId, new TimelineDragData(tvItems));
+            DragAndDrop.objectReferences = new UnityObject[] {};  // this IS required for dragging to work
+
+            string title = draggedItemIDs.Count + (draggedItemIDs.Count > 1 ? "s" : ""); // title is only shown on OSX (at the cursor)
+
+            TimelineGroupGUI groupGui = draggedNode as TimelineGroupGUI;
+            if (groupGui != null)
+            {
+                title = groupGui.displayName;
+            }
+            DragAndDrop.StartDrag(title);
+        }
+
+        public static bool IsDraggingEvent()
+        {
+            return Event.current.type == EventType.DragUpdated ||
+                Event.current.type == EventType.DragExited ||
+                Event.current.type == EventType.DragPerform;
+        }
+
+        public static bool ResolveType(IEnumerable<System.Type> types, Action<Type> onComplete, string formatString)
+        {
+            if (!types.Any() || onComplete == null)
+                return false;
+
+            if (types.Count() == 1)
+            {
+                onComplete(types.First());
+                return true;
+            }
+
+            var menu = new GenericMenu();
+
+            var builtInTypes = types.Where(TypeUtility.IsBuiltIn).OrderBy(TypeUtility.GetDisplayName).ToArray();
+            var customTypes = types.Where(x => !TypeUtility.IsBuiltIn(x)).OrderBy(TypeUtility.GetDisplayName).ToArray();
+
+            foreach (var t in builtInTypes)
+            {
+                menu.AddItem(new GUIContent(string.Format(formatString, TypeUtility.GetDisplayName(t))), false, s => onComplete((System.Type)s), t);
+            }
+
+            if (builtInTypes.Length != 0 && customTypes.Length != 0)
+                menu.AddSeparator(string.Empty);
+
+            foreach (var t in customTypes)
+            {
+                menu.AddItem(new GUIContent(string.Format(formatString, TypeUtility.GetDisplayName(t))), false, s => onComplete((System.Type)s), t);
+            }
+
+            menu.ShowAsContext();
+            return true;
+        }
+
+        public override bool DragElement(TreeViewItem targetItem, Rect targetItemRect, int row)
+        {
+            if (TimelineWindow.instance.state.editSequence.isReadOnly)
+                return false;
+            // the drop rect contains the row rect plus additional spacing. The base drag element overlaps 1/2 the height of the next track
+            // which interferes with track bindings
+            var targetTrack = targetItem as TimelineGroupGUI;
+            if (row > 0 && targetTrack != null && !targetTrack.dropRect.Contains(Event.current.mousePosition))
+                return false;
+
+            return base.DragElement(targetItem, targetItemRect, row);
+        }
+
+        TreeViewItem GetNextItem(TreeViewItem item)
+        {
+            if (item == null)
+                return null;
+
+            if (item.parent == null)
+            {
+                int row = m_Window.treeView.data.GetRow(item.id);
+                var items = m_Window.treeView.data.GetRows();
+                if (items.Count > row + 1)
+                    return items[row + 1];
+                return null;
+            }
+
+            var children = item.parent.children;
+            if (children == null)
+                return null;
+
+            for (int i = 0; i < children.Count - 1; i++)
+            {
+                if (children[i] == item)
+                    return children[i + 1];
+            }
+            return null;
+        }
+
+        private static TrackAsset GetTrack(TreeViewItem item)
+        {
+            TimelineTrackBaseGUI baseGui = item as TimelineTrackBaseGUI;
+            if (baseGui == null)
+                return null;
+            return baseGui.track;
+        }
+
+        // The drag and drop may be over an expanded group but might be between tracks
+        private void HandleNestedItemGUI(ref TreeViewItem parentItem, ref TreeViewItem targetItem, ref TreeViewItem insertBefore)
+        {
+            const float kTopPad = 5;
+            const float kBottomPad = 5;
+
+            insertBefore = null;
+
+            if (!ShouldUseHierarchyDragAndDrop())
+                return;
+
+            var targetTrack = targetItem as TimelineGroupGUI;
+            if (targetTrack == null)
+                return;
+
+            var mousePosition = Event.current.mousePosition;
+
+            var dropBefore = targetTrack.rowRect.yMin + kTopPad > mousePosition.y;
+            var dropAfter = !(targetTrack.track is GroupTrack) && (targetTrack.rowRect.yMax - kBottomPad < mousePosition.y);
+
+            targetTrack.drawInsertionMarkerBefore = dropBefore;
+            targetTrack.drawInsertionMarkerAfter = dropAfter;
+
+            if (dropBefore)
+            {
+                targetItem = parentItem;
+                parentItem = targetItem != null ? targetItem.parent : null;
+                insertBefore = targetTrack;
+            }
+            else if (dropAfter)
+            {
+                targetItem = parentItem;
+                parentItem = targetItem != null ? targetItem.parent : null;
+                insertBefore = GetNextItem(targetTrack);
+            }
+            else if (targetTrack.track is GroupTrack)
+            {
+                targetTrack.isDropTarget = true;
+            }
+        }
+
+        public override DragAndDropVisualMode DoDrag(TreeViewItem parentItem, TreeViewItem targetItem, bool perform, DropPosition dropPos)
+        {
+            m_Window.isDragging = false;
+
+            var retMode = DragAndDropVisualMode.None;
+
+            var trackDragData = DragAndDrop.GetGenericData(k_GenericDragId) as TimelineDragData;
+
+            if (trackDragData != null)
+            {
+                retMode = HandleTrackDrop(parentItem, targetItem, perform, dropPos);
+                if (retMode == DragAndDropVisualMode.Copy && targetItem != null && Event.current.type == EventType.DragUpdated)
+                {
+                    var targetActor = targetItem as TimelineGroupGUI;
+                    if (targetActor != null)
+                        targetActor.isDropTarget = true;
+                }
+            }
+            else if (DragAndDrop.objectReferences.Any())
+            {
+                var objectsBeingDropped = DragAndDrop.objectReferences.OfType<UnityObject>();
+                var director = m_Window.state.editSequence.director;
+
+                if (ShouldUseHierarchyDragAndDrop())
+                {
+                    // for object drawing
+                    var originalTarget = targetItem;
+                    TreeViewItem insertBeforeItem = null;
+                    HandleNestedItemGUI(ref parentItem, ref targetItem, ref insertBeforeItem);
+                    var track = GetTrack(targetItem);
+                    var parent = GetTrack(parentItem);
+                    var insertBefore = GetTrack(insertBeforeItem);
+                    retMode = HandleHierarchyPaneDragAndDrop(objectsBeingDropped, track, perform, m_Timeline, director, ResolveType, insertBefore);
+
+                    // fallback to old clip behaviour
+                    if (retMode == DragAndDropVisualMode.None)
+                    {
+                        retMode = HandleClipPaneObjectDragAndDrop(objectsBeingDropped, track, perform, m_Timeline, parent, director, m_Window.state.timeAreaShownRange.x, ResolveType, insertBefore);
+                    }
+
+                    // if we are rejected, clear any drop markers
+                    if (retMode == DragAndDropVisualMode.Rejected && targetItem != null)
+                    {
+                        ClearInsertionMarkers(originalTarget);
+                        ClearInsertionMarkers(targetItem);
+                        ClearInsertionMarkers(parentItem);
+                        ClearInsertionMarkers(insertBeforeItem);
+                    }
+                }
+                else
+                {
+                    var candidateTime = TimelineHelpers.GetCandidateTime(m_Window.state, Event.current.mousePosition);
+                    retMode = HandleClipPaneObjectDragAndDrop(objectsBeingDropped, GetTrack(targetItem), perform, m_Timeline, GetTrack(parentItem), director, candidateTime, ResolveType);
+                }
+            }
+
+            m_Window.isDragging = false;
+
+            return retMode;
+        }
+
+        void ClearInsertionMarkers(TreeViewItem item)
+        {
+            var trackGUI = item as TimelineTrackBaseGUI;
+            if (trackGUI != null)
+            {
+                trackGUI.drawInsertionMarkerAfter = false;
+                trackGUI.drawInsertionMarkerBefore = false;
+                trackGUI.isDropTarget = false;
+            }
+        }
+
+        bool ShouldUseHierarchyDragAndDrop()
+        {
+            return m_Window.state.IsEditingAnEmptyTimeline() || m_Window.state.sequencerHeaderWidth > Event.current.mousePosition.x;
+        }
+
+        public static DragAndDropVisualMode HandleHierarchyPaneDragAndDrop(IEnumerable<UnityObject> objectsBeingDropped, TrackAsset targetTrack, bool perform, TimelineAsset timeline, PlayableDirector director, TypeResolver typeResolver, TrackAsset insertBefore = null)
+        {
+            if (timeline == null)
+                return DragAndDropVisualMode.Rejected;
+
+            // if we are over a target track, defer to track binding system (implemented in TrackGUIs), unless we are a groupTrack
+            if (targetTrack != null && (targetTrack as GroupTrack) == null)
+                return DragAndDropVisualMode.None;
+
+            if (targetTrack != null && targetTrack.lockedInHierarchy)
+                return DragAndDropVisualMode.Rejected;
+
+            var tracksWithBinding = objectsBeingDropped.SelectMany(TypeUtility.GetTracksCreatableFromObject).Distinct();
+            if (!tracksWithBinding.Any())
+                return DragAndDropVisualMode.None;
+
+            if (perform)
+            {
+                System.Action<Type> onResolve = trackType =>
+                {
+                    foreach (var obj in objectsBeingDropped)
+                    {
+                        if (!obj.IsPrefab() && TypeUtility.IsTrackCreatableFromObject(obj, trackType))
+                        {
+                            var newTrack = TimelineHelpers.CreateTrack(timeline, trackType, targetTrack, string.Empty);
+                            if (insertBefore != null)
+                            {
+                                if (targetTrack != null)
+                                    targetTrack.MoveLastTrackBefore(insertBefore);
+                                else
+                                    timeline.MoveLastTrackBefore(insertBefore);
+                            }
+
+                            TimelineHelpers.Bind(newTrack, obj, director);
+                        }
+                    }
+                    TimelineEditor.Refresh(RefreshReason.ContentsAddedOrRemoved);
+                };
+                typeResolver(tracksWithBinding, onResolve, k_SelectTrackWithBinding);
+            }
+
+            return DragAndDropVisualMode.Copy;
+        }
+
+        public static DragAndDropVisualMode HandleClipPaneObjectDragAndDrop(IEnumerable<UnityObject> objectsBeingDropped, TrackAsset targetTrack, bool perform, TimelineAsset timeline, TrackAsset parent, PlayableDirector director, double candidateTime, TypeResolver typeResolver, TrackAsset insertBefore = null)
+        {
+            if (timeline == null)
+                return DragAndDropVisualMode.Rejected;
+
+            // locked tracks always reject
+            if (targetTrack != null && targetTrack.lockedInHierarchy)
+                return DragAndDropVisualMode.Rejected;
+
+            // treat group tracks as having no track
+            if (targetTrack is GroupTrack)
+            {
+                parent = targetTrack;
+                targetTrack = null;
+            }
+
+            // Special case for monoscripts, since they describe the type
+            if (objectsBeingDropped.Any(o => o is MonoScript))
+                return HandleClipPaneMonoScriptDragAndDrop(objectsBeingDropped.OfType<MonoScript>(), targetTrack, perform, timeline, parent, director, candidateTime);
+
+            // no unity objects, or explicit exceptions
+            if (!objectsBeingDropped.Any() || objectsBeingDropped.Any(o => !ValidateObjectDrop(o)))
+                return DragAndDropVisualMode.Rejected;
+
+            // reject scene references if we have no context
+            if (director == null && objectsBeingDropped.Any(o => o.IsSceneObject()))
+                return DragAndDropVisualMode.Rejected;
+
+            var validTrackTypes = objectsBeingDropped.SelectMany(o => TypeUtility.GetTrackTypesForObject(o)).Distinct().ToList();
+            // special case for playable assets
+            if (objectsBeingDropped.Any(o => TypeUtility.IsConcretePlayableAsset(o.GetType())))
+            {
+                var playableAssets = objectsBeingDropped.OfType<IPlayableAsset>().Where(o => TypeUtility.IsConcretePlayableAsset(o.GetType()));
+                return HandleClipPanePlayableAssetDragAndDrop(playableAssets, targetTrack, perform, timeline, parent, director, candidateTime, typeResolver);
+            }
+
+            var markerTypes = objectsBeingDropped.SelectMany(o => TypeUtility.MarkerTypesWithFieldForObject(o)).Distinct();
+
+            // Markers support all tracks
+            if (!markerTypes.Any())
+            {
+                // No tracks support this object
+                if (!validTrackTypes.Any())
+                    return DragAndDropVisualMode.Rejected;
+
+                // no tracks for this object
+                if (targetTrack != null && !validTrackTypes.Contains(targetTrack.GetType()))
+                    return DragAndDropVisualMode.Rejected;
+            }
+
+            // there is no target track, dropping to empty space, or onto a group
+            if (perform)
+            {
+                // choose track and then clip
+                if (targetTrack == null)
+                {
+                    var createdTrack = HandleTrackAndItemCreation(objectsBeingDropped, candidateTime, typeResolver, timeline, parent, validTrackTypes, insertBefore);
+                    if (!createdTrack)
+                    {
+                        timeline.CreateMarkerTrack();
+                        HandleItemCreation(objectsBeingDropped, timeline.markerTrack, candidateTime, typeResolver, true); // menu is always popped if ambiguous choice
+                    }
+                }
+                // just choose clip/marker
+                else
+                {
+                    HandleItemCreation(objectsBeingDropped, targetTrack, candidateTime, typeResolver, true); // menu is always popped if ambiguous choice
+                }
+            }
+
+            return DragAndDropVisualMode.Copy;
+        }
+
+        static bool HandleTrackAndItemCreation(IEnumerable<UnityEngine.Object> objectsBeingDropped, double candidateTime, TypeResolver typeResolver, TimelineAsset timeline, TrackAsset parent, IEnumerable<Type> validTrackTypes, TrackAsset insertBefore = null)
+        {
+            Action<Type> onResolved = t =>
+            {
+                var newTrack = TimelineHelpers.CreateTrack(timeline, t, parent, string.Empty);
+                if (insertBefore != null)
+                {
+                    if (parent != null)
+                        parent.MoveLastTrackBefore(insertBefore);
+                    else
+                        timeline.MoveLastTrackBefore(insertBefore);
+                }
+                HandleItemCreation(objectsBeingDropped, newTrack, candidateTime, typeResolver, validTrackTypes.Count() == 1); // menu is popped if ambiguous clip choice and unambiguous track choice
+            };
+            return typeResolver(validTrackTypes, t => onResolved(t), k_SelectTrackWithClip); // Did it create a track
+        }
+
+        static void HandleItemCreation(IEnumerable<UnityEngine.Object> objectsBeingDropped, TrackAsset targetTrack, double candidateTime, TypeResolver typeResolver, bool allowMenu)
+        {
+            var assetTypes = objectsBeingDropped.Select(o =>
+                TypeUtility.GetAssetTypesForObject(targetTrack.GetType(), o)
+                    .Union(TypeUtility.MarkerTypesWithFieldForObject(o))).ToList();
+            Action<Type> onCreateItem = assetType =>
+            {
+                if (typeof(PlayableAsset).IsAssignableFrom(assetType))
+                {
+                    TimelineHelpers.CreateClipsFromObjects(assetType, targetTrack, candidateTime,
+                        objectsBeingDropped);
+                }
+                else
+                {
+                    TimelineHelpers.CreateMarkersFromObjects(assetType, targetTrack, candidateTime, objectsBeingDropped);
+                }
+            };
+
+            var flatAssetTypes = assetTypes.SelectMany(x => x).Distinct();
+            // If there is a one to one mapping between assets and timeline types, no need to go through the type resolution, not ambiguous.
+            if (assetTypes.All(x => x.Count() <= 1))
+            {
+                foreach (var type in flatAssetTypes)
+                {
+                    onCreateItem(type);
+                }
+            }
+            else
+            {
+                if (!allowMenu) // If we already popped a menu, and are presented with an ambiguous choice, take the first entry
+                {
+                    flatAssetTypes = new[] {flatAssetTypes.First()};
+                }
+
+                typeResolver(flatAssetTypes, onCreateItem, k_SelectClip);
+            }
+        }
+
+        /// Handles drag and drop of a mono script.
+        public static DragAndDropVisualMode HandleClipPaneMonoScriptDragAndDrop(IEnumerable<MonoScript> scriptsBeingDropped, TrackAsset targetTrack, bool perform, TimelineAsset timeline, TrackAsset parent, PlayableDirector director, double candidateTime)
+        {
+            var playableAssetTypes = scriptsBeingDropped.Select(s => s.GetClass()).Where(TypeUtility.IsConcretePlayableAsset).Distinct();
+            if (!playableAssetTypes.Any())
+                return DragAndDropVisualMode.Rejected;
+
+            var targetTrackType = typeof(PlayableTrack);
+            if (targetTrack != null)
+                targetTrackType = targetTrack.GetType();
+
+            var trackAssetsTypes = TypeUtility.GetPlayableAssetsHandledByTrack(targetTrackType);
+            var supportedTypes = trackAssetsTypes.Intersect(playableAssetTypes);
+            if (!supportedTypes.Any())
+                return DragAndDropVisualMode.Rejected;
+
+            if (perform)
+            {
+                if (targetTrack == null)
+                    targetTrack = TimelineHelpers.CreateTrack(timeline, targetTrackType, parent, string.Empty);
+                TimelineHelpers.CreateClipsFromTypes(supportedTypes, targetTrack, candidateTime);
+            }
+
+            return DragAndDropVisualMode.Copy;
+        }
+
+        public static DragAndDropVisualMode HandleClipPanePlayableAssetDragAndDrop(IEnumerable<IPlayableAsset> assetsBeingDropped, TrackAsset targetTrack, bool perform, TimelineAsset timeline, TrackAsset parent, PlayableDirector director, double candidateTime, TypeResolver typeResolver)
+        {
+            // get the list of supported track types
+            var assetTypes = assetsBeingDropped.Select(x => x.GetType()).Distinct();
+            IEnumerable<Type> supportedTypes = null;
+            if (targetTrack == null)
+            {
+                supportedTypes = TypeUtility.AllTrackTypes().Where(t => TypeUtility.GetPlayableAssetsHandledByTrack(t).Intersect(assetTypes).Any()).ToList();
+            }
+            else
+            {
+                supportedTypes = Enumerable.Empty<Type>();
+                var trackAssetTypes = TypeUtility.GetPlayableAssetsHandledByTrack(targetTrack.GetType());
+                if (trackAssetTypes.Intersect(assetTypes).Any())
+                    supportedTypes = new[] {targetTrack.GetType()};
+            }
+
+            if (!supportedTypes.Any())
+                return DragAndDropVisualMode.Rejected;
+
+            if (perform)
+            {
+                Action<Type> onResolved = (t) =>
+                {
+                    if (targetTrack == null)
+                        targetTrack = TimelineHelpers.CreateTrack(timeline, t, parent, string.Empty);
+
+                    var clipTypes = TypeUtility.GetPlayableAssetsHandledByTrack(targetTrack.GetType());
+                    foreach (var asset in assetsBeingDropped)
+                    {
+                        if (clipTypes.Contains(asset.GetType()))
+                            TimelineHelpers.CreateClipOnTrackFromPlayableAsset(asset, targetTrack, candidateTime);
+                    }
+                };
+
+                typeResolver(supportedTypes, onResolved, k_SelectTrackWithClip);
+            }
+
+
+            return DragAndDropVisualMode.Copy;
+        }
+
+        static bool ValidateObjectDrop(UnityObject obj)
+        {
+            // legacy animation clips are not supported at all
+            AnimationClip clip = obj as AnimationClip;
+            if (clip != null && clip.legacy)
+                return false;
+
+            return !(obj is TimelineAsset);
+        }
+
+        public DragAndDropVisualMode HandleTrackDrop(TreeViewItem parentItem, TreeViewItem targetItem, bool perform, DropPosition dropPos)
+        {
+            ((TimelineTreeView)m_Window.treeView.gui).showInsertionMarker = false;
+            var trackDragData = (TimelineDragData)DragAndDrop.GetGenericData(k_GenericDragId);
+            bool validDrag = ValidDrag(targetItem, trackDragData.draggedItems);
+            if (!validDrag)
+                return DragAndDropVisualMode.None;
+
+
+            var draggedTracks = trackDragData.draggedItems.OfType<TimelineGroupGUI>().Select(x => x.track).ToList();
+            if (draggedTracks.Count == 0)
+                return DragAndDropVisualMode.None;
+
+            if (parentItem != null)
+            {
+                var parentActor = parentItem as TimelineGroupGUI;
+                if (parentActor != null && parentActor.track != null)
+                {
+                    if (parentActor.track.lockedInHierarchy)
+                        return DragAndDropVisualMode.Rejected;
+
+                    if (draggedTracks.Any(x => !TimelineCreateUtilities.ValidateParentTrack(parentActor.track, x.GetType())))
+                        return DragAndDropVisualMode.Rejected;
+                }
+            }
+
+            var insertAfterItem = targetItem as TimelineGroupGUI;
+            if (insertAfterItem != null && insertAfterItem.track != null)
+            {
+                ((TimelineTreeView)m_Window.treeView.gui).showInsertionMarker = true;
+            }
+
+            if (dropPos == DropPosition.Upon)
+            {
+                var groupGUI = targetItem as TimelineGroupGUI;
+                if (groupGUI != null)
+                    groupGUI.isDropTarget = true;
+            }
+
+            if (perform)
+            {
+                PlayableAsset targetParent = m_Timeline;
+                var parentActor = parentItem as TimelineGroupGUI;
+
+                if (parentActor != null && parentActor.track != null)
+                    targetParent = parentActor.track;
+
+                TrackAsset siblingTrack = insertAfterItem != null ? insertAfterItem.track : null;
+
+                // where the user drops after the last track, make sure to place it after all the tracks
+                if (targetParent == m_Timeline && dropPos == DropPosition.Below && siblingTrack == null)
+                {
+                    siblingTrack = m_Timeline.GetRootTracks().LastOrDefault(x => !draggedTracks.Contains(x));
+                }
+
+                if (TrackExtensions.ReparentTracks(TrackExtensions.FilterTracks(draggedTracks).ToList(), targetParent, siblingTrack, dropPos == DropPosition.Above))
+                {
+                    m_Window.state.Refresh();
+                }
+            }
+
+            return DragAndDropVisualMode.Move;
+        }
+
+        public static void HandleBindingDragAndDrop(TrackAsset dropTarget, Type requiredBindingType)
+        {
+            var objectBeingDragged = DragAndDrop.objectReferences[0];
+
+            var action = BindingUtility.GetBindingAction(requiredBindingType, objectBeingDragged);
+            DragAndDrop.visualMode = action == BindingAction.DoNotBind
+                ? DragAndDropVisualMode.Rejected
+                : DragAndDropVisualMode.Link;
+
+            if (action == BindingAction.DoNotBind || Event.current.type != EventType.DragPerform)
+                return;
+
+            var director = TimelineEditor.inspectedDirector;
+
+            switch (action)
+            {
+                case BindingAction.BindDirectly:
+                {
+                    BindingUtility.Bind(director, dropTarget, objectBeingDragged);
+                    break;
+                }
+                case BindingAction.BindToExistingComponent:
+                {
+                    var gameObjectBeingDragged = objectBeingDragged as GameObject;
+                    Debug.Assert(gameObjectBeingDragged != null, "The object being dragged was detected as being a GameObject");
+
+                    BindingUtility.Bind(director, dropTarget, gameObjectBeingDragged.GetComponent(requiredBindingType));
+                    break;
+                }
+                case BindingAction.BindToMissingComponent:
+                {
+                    var gameObjectBeingDragged = objectBeingDragged as GameObject;
+                    Debug.Assert(gameObjectBeingDragged != null, "The object being dragged was detected as being a GameObject");
+
+                    var typeNameOfComponent = requiredBindingType.ToString().Split(".".ToCharArray()).Last();
+                    var bindMenu = new GenericMenu();
+
+                    bindMenu.AddItem(
+                        EditorGUIUtility.TextContent("Create " + typeNameOfComponent + " on " + gameObjectBeingDragged.name),
+                        false,
+                        nullParam => BindingUtility.Bind(director, dropTarget, Undo.AddComponent(gameObjectBeingDragged, requiredBindingType)),
+                        null);
+
+                    bindMenu.AddSeparator("");
+                    bindMenu.AddItem(EditorGUIUtility.TrTextContent("Cancel"), false, userData => {}, null);
+                    bindMenu.ShowAsContext();
+
+                    break;
+                }
+                default:
+                {
+                    //no-op
+                    return;
+                }
+            }
+
+            DragAndDrop.AcceptDrag();
+        }
+
+        static bool ValidDrag(TreeViewItem target, List<TreeViewItem> draggedItems)
+        {
+            TreeViewItem currentParent = target;
+            while (currentParent != null)
+            {
+                if (draggedItems.Contains(currentParent))
+                    return false;
+                currentParent = currentParent.parent;
+            }
+
+            // dragging into the sequence itself
+            return true;
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineDragging.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineDragging.cs.meta
new file mode 100644
index 0000000..4aff0f8
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineDragging.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: fcd66bf74cbeb264aa99679c7df84427
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineGroupGUI.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineGroupGUI.cs
new file mode 100644
index 0000000..8341b8b
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineGroupGUI.cs
@@ -0,0 +1,310 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using UnityEditor.IMGUI.Controls;
+using UnityEngine;
+using UnityEngine.Timeline;
+
+namespace UnityEditor.Timeline
+{
+    class TimelineGroupGUI : TimelineTrackBaseGUI
+    {
+        protected DirectorStyles m_Styles;
+        protected Rect m_TreeViewRect = new Rect(0, 0, 0, 0);
+        protected GUIContent m_ProblemIcon = new GUIContent();
+
+        bool m_MustRecomputeUnions = true;
+        int m_GroupDepth;
+        readonly bool m_IsReferencedTrack;
+        readonly List<TimelineClipUnion> m_Unions = new List<TimelineClipUnion>();
+
+        public override Rect boundingRect
+        {
+            get { return ToWindowSpace(m_TreeViewRect); }
+        }
+
+        public Rect ToWindowSpace(Rect localRect)
+        {
+            localRect.position += treeViewToWindowTransformation;
+            return localRect;
+        }
+
+        public override bool expandable
+        {
+            get { return !m_IsRoot; }
+        }
+
+        // The expanded rectangle (contains children) as calculated by the the tree gui
+        public Rect expandedRect { get; set; }
+        // The row rectangle (header only) as calculated by the tree gui
+        public Rect rowRect { get; set; }
+        // the drop rectangle as set by the tree gui when targetted by a drag and drop
+        public Rect dropRect { get; set; }
+
+        public TimelineGroupGUI(TreeViewController treeview, TimelineTreeViewGUI treeviewGUI, int id, int depth, TreeViewItem parent, string displayName, TrackAsset trackAsset, bool isRoot)
+            : base(id, depth, parent, displayName, trackAsset, treeview, treeviewGUI)
+        {
+            m_Styles = DirectorStyles.Instance;
+            m_IsRoot = isRoot;
+
+            var trackPath = AssetDatabase.GetAssetPath(trackAsset);
+            var sequencePath = AssetDatabase.GetAssetPath(treeviewGUI.TimelineWindow.state.editSequence.asset);
+            if (trackPath != sequencePath)
+                m_IsReferencedTrack = true;
+
+            m_GroupDepth = CalculateGroupDepth(parent);
+        }
+
+        public virtual float GetHeight(WindowState state)
+        {
+            // group tracks don't scale in height
+            return TrackEditor.DefaultTrackHeight;
+        }
+
+        public override void OnGraphRebuilt() {}
+
+        static int CalculateGroupDepth(TreeViewItem parent)
+        {
+            int depth = 0;
+
+            bool done = false;
+            do
+            {
+                var gui = parent as TimelineGroupGUI;
+                if (gui == null || gui.track == null)
+                    done = true;
+                else
+                {
+                    if (gui.track is GroupTrack)
+                        depth++;
+
+                    parent = parent.parent;
+                }
+            }
+            while (!done);
+
+            return depth;
+        }
+
+        internal static float Spaced(float width)
+        {
+            return width > 0 ? width + WindowConstants.trackHeaderButtonSpacing : 0;
+        }
+
+        void DrawTrackButtons(Rect headerRect, WindowState state)
+        {
+            const float buttonSize = WindowConstants.trackHeaderButtonSize;
+            const float padding = WindowConstants.trackHeaderButtonPadding;
+
+            var buttonRect = new Rect(headerRect.xMax - buttonSize - padding, headerRect.y + ((headerRect.height - buttonSize) / 2f), buttonSize, buttonSize);
+
+            if (GUI.Button(buttonRect, EditorGUIUtility.IconContent("CreateAddNew"), m_Styles.trackGroupAddButton))
+            {
+                // the drop down will apply to all selected tracks
+                if (!SelectionManager.Contains(track))
+                {
+                    SelectionManager.Clear();
+                    SelectionManager.Add(track);
+                }
+                SequencerContextMenu.ShowNewTracksContextMenu(SelectionManager.SelectedTracks().ToArray(), TimelineWindow.state, buttonRect);
+            }
+            buttonRect.x -= buttonSize;
+            buttonRect.x -= Spaced(DrawMuteButton(buttonRect, state));
+            buttonRect.x -= Spaced(DrawLockButton(buttonRect, state));
+        }
+
+        public void SetExpanded(bool expanded)
+        {
+            var collapseChanged = expanded != isExpanded;
+            isExpanded = expanded;
+            if (collapseChanged)
+            {
+                track.SetCollapsed(!expanded);
+                m_MustRecomputeUnions = true;
+            }
+        }
+
+        public override void Draw(Rect headerRect, Rect contentRect, WindowState state)
+        {
+            if (track == null || m_IsRoot)
+                return;
+
+            if (m_MustRecomputeUnions)
+                RecomputeRectUnions();
+
+            if (depth == 1)
+                Graphics.DrawBackgroundRect(state, headerRect);
+
+            var background = headerRect;
+            background.height = expandedRect.height;
+
+            var groupColor = TrackResourceCache.GetTrackColor(track);
+
+            m_TreeViewRect = contentRect;
+
+            var col = groupColor;
+
+            var isSelected = SelectionManager.Contains(track);
+
+            if (isSelected)
+                col = DirectorStyles.Instance.customSkin.colorSelection;
+            else if (isDropTarget)
+                col = DirectorStyles.Instance.customSkin.colorDropTarget;
+            else
+            {
+                if (m_GroupDepth % 2 == 1)
+                {
+                    float h, s, v;
+                    Color.RGBToHSV(col, out h, out s, out v);
+                    v += 0.06f;
+                    col = Color.HSVToRGB(h, s, v);
+                }
+            }
+
+            if (background.width > 0)
+            {
+                using (new GUIColorOverride(col))
+                    GUI.Box(background, GUIContent.none, m_Styles.groupBackground);
+            }
+
+            var trackRectBackground = headerRect;
+            trackRectBackground.xMin += background.width;
+            trackRectBackground.width = contentRect.width;
+            trackRectBackground.height = background.height;
+
+            if (isSelected)
+            {
+                col = state.IsEditingASubTimeline()
+                    ? m_Styles.customSkin.colorTrackSubSequenceBackgroundSelected
+                    : m_Styles.customSkin.colorTrackBackgroundSelected;
+            }
+            else
+            {
+                col = m_Styles.customSkin.colorGroupTrackBackground;
+            }
+
+            EditorGUI.DrawRect(trackRectBackground, col);
+            if (!isExpanded && children != null && children.Count > 0)
+            {
+                var collapsedTrackRect = contentRect;
+
+                foreach (var u in m_Unions)
+                    u.Draw(collapsedTrackRect, state);
+            }
+
+            using (new GUIGroupScope(headerRect))
+            {
+                var groupRect = new Rect(0, 0, headerRect.width, headerRect.height);
+                DrawName(groupRect, isSelected);
+                DrawTrackButtons(groupRect, state);
+            }
+
+            if (IsTrackRecording(state))
+            {
+                using (new GUIColorOverride(DirectorStyles.Instance.customSkin.colorTrackBackgroundRecording))
+                    GUI.Label(background, GUIContent.none, m_Styles.displayBackground);
+            }
+
+            // is this a referenced track?
+            if (m_IsReferencedTrack)
+            {
+                var refRect = contentRect;
+                refRect.x = state.timeAreaRect.xMax - 20.0f;
+                refRect.y += 5.0f;
+                refRect.width = 30.0f;
+                GUI.Label(refRect, DirectorStyles.referenceTrackLabel, EditorStyles.label);
+            }
+
+            var bgRect = contentRect;
+            if (track as GroupTrack != null || AllChildrenMuted(this))
+                bgRect.height = expandedRect.height;
+            DrawTrackState(contentRect, bgRect, track);
+        }
+
+        void DrawName(Rect rect, bool isSelected)
+        {
+            var labelRect = rect;
+            labelRect.xMin += 20;
+            var actorName = track != null ? track.name : "missing";
+            labelRect.width = m_Styles.groupFont.CalcSize(new GUIContent(actorName)).x;
+            labelRect.width = Math.Max(labelRect.width, 50.0f);
+
+            // if we aren't bound to anything, we show a text field that allows to rename the actor
+            // otherwise we show a ObjectField to allow binding to a go
+            if (track != null && track is GroupTrack)
+            {
+                var textColor = m_Styles.groupFont.normal.textColor;
+
+                if (isSelected)
+                    textColor = Color.white;
+
+                string newName;
+
+                EditorGUI.BeginChangeCheck();
+                using (new StyleNormalColorOverride(m_Styles.groupFont, textColor))
+                {
+                    newName = EditorGUI.DelayedTextField(labelRect, GUIContent.none, track.GetInstanceID(), track.name, m_Styles.groupFont);
+                }
+
+                if (EditorGUI.EndChangeCheck() && !string.IsNullOrEmpty(newName))
+                {
+                    track.name = newName;
+                    displayName = track.name;
+                }
+            }
+        }
+
+        protected bool IsSubTrack()
+        {
+            if (track == null)
+                return false;
+
+            var parentTrack = track.parent as TrackAsset;
+            if (parentTrack == null)
+                return false;
+
+            return parentTrack.GetType() != typeof(GroupTrack);
+        }
+
+        protected TrackAsset ParentTrack()
+        {
+            if (IsSubTrack())
+                return track.parent as TrackAsset;
+            return null;
+        }
+
+        // is there currently a recording track
+        bool IsTrackRecording(WindowState state)
+        {
+            if (!state.recording)
+                return false;
+            if (track.GetType() != typeof(GroupTrack))
+                return false;
+
+            return state.GetArmedTrack(track) != null;
+        }
+
+        void RecomputeRectUnions()
+        {
+            m_MustRecomputeUnions = false;
+            m_Unions.Clear();
+            if (children == null)
+                return;
+
+            foreach (var c in children.OfType<TimelineTrackGUI>())
+            {
+                c.RebuildGUICacheIfNecessary();
+                m_Unions.AddRange(TimelineClipUnion.Build(c.clips));
+            }
+        }
+
+        static bool AllChildrenMuted(TimelineGroupGUI groupGui)
+        {
+            if (!groupGui.track.muted)
+                return false;
+            if (groupGui.children == null)
+                return true;
+            return groupGui.children.OfType<TimelineGroupGUI>().All(AllChildrenMuted);
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineGroupGUI.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineGroupGUI.cs.meta
new file mode 100644
index 0000000..470f3aa
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineGroupGUI.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 00187582b67e7654b914b5a0d37daafb
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineTrackBaseGUI.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineTrackBaseGUI.cs
new file mode 100644
index 0000000..b957f33
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineTrackBaseGUI.cs
@@ -0,0 +1,218 @@
+using System.Linq;
+using UnityEditor.IMGUI.Controls;
+using UnityEngine;
+using UnityEngine.Timeline;
+
+namespace UnityEditor.Timeline
+{
+    abstract class TimelineTrackBaseGUI : TreeViewItem, IBounds
+    {
+        static class Styles
+        {
+            public static readonly GUIContent s_LockedAndMuted = EditorGUIUtility.TrTextContent("Locked / Muted");
+            public static readonly GUIContent s_LockedAndPartiallyMuted = EditorGUIUtility.TrTextContent("Locked / Partially Muted");
+            public static readonly GUIContent s_Locked = EditorGUIUtility.TrTextContent("Locked");
+            public static readonly GUIContent s_Muted = EditorGUIUtility.TrTextContent("Muted");
+            public static readonly GUIContent s_PartiallyMuted = EditorGUIUtility.TrTextContent("Partially Muted");
+
+            public static readonly Texture2D lockBg = DirectorStyles.GetBackgroundImage(DirectorStyles.Instance.lockedBG);
+        }
+
+        protected bool m_IsRoot = false;
+        protected const float k_ButtonSize = 16.0f;
+
+        readonly TimelineTreeViewGUI m_TreeViewGUI;
+        readonly TrackDrawer m_Drawer;
+
+        public Vector2 treeViewToWindowTransformation { get; set; }
+        public bool isExpanded { get; set; }
+        public bool isDropTarget { protected get; set; }
+        public TrackAsset track { get; }
+        TreeViewController treeView { get; }
+
+        public TimelineWindow TimelineWindow
+        {
+            get
+            {
+                if (m_TreeViewGUI == null)
+                    return null;
+
+                return m_TreeViewGUI.TimelineWindow;
+            }
+        }
+
+        public TrackDrawer drawer
+        {
+            get { return m_Drawer; }
+        }
+
+        public virtual float GetVerticalSpacingBetweenTracks()
+        {
+            return 3.0f;
+        }
+
+        public bool visibleRow { get; set; }        // is the header row visible
+        public bool visibleExpanded { get; set; }   // is the expanded area (group) visible
+        public bool drawInsertionMarkerBefore { get; set; }
+        public bool drawInsertionMarkerAfter  { get; set; }
+
+        public abstract Rect boundingRect { get; }
+        public abstract bool expandable { get; }
+        public abstract void Draw(Rect headerRect, Rect contentRect, WindowState state);
+        public abstract void OnGraphRebuilt(); // callback when the corresponding graph is rebuilt. This can happen, but not have the GUI rebuilt.
+
+        protected TimelineTrackBaseGUI(int id, int depth, TreeViewItem parent, string displayName, TrackAsset trackAsset, TreeViewController tv, TimelineTreeViewGUI tvgui)
+            : base(id, depth, parent, displayName)
+        {
+            m_Drawer = TrackDrawer.CreateInstance(trackAsset);
+            m_Drawer.sequencerState = tvgui.TimelineWindow.state;
+
+            isExpanded = false;
+            isDropTarget = false;
+            track = trackAsset;
+            treeView = tv;
+
+            m_TreeViewGUI = tvgui;
+        }
+
+        public static TimelineTrackBaseGUI FindGUITrack(TrackAsset track)
+        {
+            var allTracks = TimelineWindow.instance.allTracks;
+            return allTracks.Find(x => x.track == track);
+        }
+
+        protected void DrawTrackState(Rect trackRect, Rect expandedRect, TrackAsset track)
+        {
+            if (Event.current.type == EventType.Layout)
+            {
+                bool needStateBox = false;
+
+                //Mute
+                if (track.muted && !TimelineUtility.IsParentMuted(track))
+                {
+                    Rect bgRect = expandedRect;
+                    TimelineWindow.instance.OverlayDrawData.Add(TimelineWindow.OverlayData.CreateColorOverlay(GUIClip.Unclip(bgRect), DirectorStyles.Instance.customSkin.colorTrackDarken));
+                    needStateBox = true;
+                }
+
+                //Lock
+                if (!needStateBox && track.locked && !TimelineUtility.IsLockedFromGroup(track))
+                {
+                    Rect bgRect = expandedRect;
+                    TimelineWindow.instance.OverlayDrawData.Add(TimelineWindow.OverlayData.CreateTextureOverlay(GUIClip.Unclip(bgRect), Styles.lockBg));
+                    needStateBox = true;
+                }
+
+                if (needStateBox)
+                {
+                    DrawTrackStateBox(trackRect, track);
+                }
+            }
+        }
+
+        void DrawTrackStateBox(Rect trackRect, TrackAsset track)
+        {
+            const float k_LockTextPadding = 40f;
+            var styles = DirectorStyles.Instance;
+
+            bool locked = track.locked && !TimelineUtility.IsLockedFromGroup(track);
+            bool muted = track.muted && !TimelineUtility.IsParentMuted(track);
+            bool allSubTrackMuted = TimelineUtility.IsAllSubTrackMuted(track);
+
+            GUIContent content = null;
+            if (locked && muted)
+            {
+                content = Styles.s_LockedAndMuted;
+                if (!allSubTrackMuted)
+                    content = Styles.s_LockedAndPartiallyMuted;
+            }
+            else if (locked) content = Styles.s_Locked;
+            else if (muted)
+            {
+                content = Styles.s_Muted;
+                if (!allSubTrackMuted)
+                    content = Styles.s_PartiallyMuted;
+            }
+
+            // the track could be locked, but we only show the 'locked portion' on the upper most track
+            //  that is causing the lock
+            if (content == null)
+                return;
+
+            var textRect = trackRect;
+            textRect.width = styles.fontClip.CalcSize(content).x + k_LockTextPadding;
+            textRect.x += (trackRect.width - textRect.width) / 2f;
+            textRect.height -= 4f;
+            textRect.y += 2f;
+
+
+            TimelineWindow.instance.OverlayDrawData.Add(TimelineWindow.OverlayData.CreateTextBoxOverlay(GUIClip.Unclip(textRect), content.text, styles.fontClip, Color.white, styles.customSkin.colorLockTextBG, styles.displayBackground));
+        }
+
+        protected float DrawMuteButton(Rect rect, WindowState state)
+        {
+            if (track.mutedInHierarchy)
+            {
+                using (new EditorGUI.DisabledScope(TimelineUtility.IsParentMuted(track)))
+                {
+                    if (GUI.Button(rect, GUIContent.none, TimelineWindow.styles.mute))
+                    {
+                        MuteTrack.Mute(state, new[] { track }, false);
+                    }
+                }
+
+                return WindowConstants.trackHeaderButtonSize;
+            }
+
+            return 0.0f;
+        }
+
+        protected float DrawLockButton(Rect rect, WindowState state)
+        {
+            if (track.lockedInHierarchy)
+            {
+                // if the parent is locked, show it the lock disabled
+                using (new EditorGUI.DisabledScope(TimelineUtility.IsLockedFromGroup(track)))
+                {
+                    if (GUI.Button(rect, GUIContent.none, TimelineWindow.styles.locked))
+                    {
+                        LockTrack.SetLockState(new[] { track }, !track.locked, state);
+                    }
+                }
+
+                return WindowConstants.trackHeaderButtonSize;
+            }
+
+            return 0.0f;
+        }
+
+        public void DrawInsertionMarkers(Rect rowRectWithIndent)
+        {
+            const float insertionHeight = WindowConstants.trackInsertionMarkerHeight;
+            if (Event.current.type == EventType.Repaint && (drawInsertionMarkerAfter || drawInsertionMarkerBefore))
+            {
+                if (drawInsertionMarkerBefore)
+                {
+                    var rect = new Rect(rowRectWithIndent.x, rowRectWithIndent.y - insertionHeight * 0.5f - 2.0f, rowRectWithIndent.width, insertionHeight);
+                    EditorGUI.DrawRect(rect, Color.white);
+                }
+
+                if (drawInsertionMarkerAfter)
+                {
+                    var rect = new Rect(rowRectWithIndent.x, rowRectWithIndent.y + rowRectWithIndent.height - insertionHeight * 0.5f + 1.0f, rowRectWithIndent.width, insertionHeight);
+                    EditorGUI.DrawRect(rect, Color.white);
+                }
+            }
+        }
+
+        public void ClearDrawFlags()
+        {
+            if (Event.current.type == EventType.Repaint)
+            {
+                isDropTarget = false;
+                drawInsertionMarkerAfter = false;
+                drawInsertionMarkerBefore = false;
+            }
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineTrackBaseGUI.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineTrackBaseGUI.cs.meta
new file mode 100644
index 0000000..50e7b73
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineTrackBaseGUI.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 9b1a3034a9e81704abdd08677a2d035f
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineTrackErrorGUI.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineTrackErrorGUI.cs
new file mode 100644
index 0000000..7e32e2c
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineTrackErrorGUI.cs
@@ -0,0 +1,185 @@
+using System;
+using UnityEditor.IMGUI.Controls;
+using UnityEngine;
+using UnityEngine.Playables;
+
+namespace UnityEditor.Timeline
+{
+    class TimelineTrackErrorGUI : TimelineTrackBaseGUI
+    {
+        static class Styles
+        {
+            public static readonly GUIContent ErrorText = EditorGUIUtility.TrTextContent("Track cannot be loaded.", "Please fix any compile errors in the script for this track");
+            public static readonly Texture2D IconWarn = EditorGUIUtility.LoadIconRequired("console.warnicon.inactive.sml");
+            public static readonly GUIContent RemoveTrack = EditorGUIUtility.TrTextContent("Delete");
+
+            public static readonly Color WarningBoxBackgroundColor = new Color(115.0f / 255.0f, 115.0f / 255.0f, 115.0f / 255.0f); // approved for both skins
+            public static readonly Color WarningBoxHighlightColor = new Color(229 / 255.0f, 208 / 255.0f, 54 / 255.0f); // brigher than standard warning color for contrast
+        }
+
+        Rect m_TrackRect;
+        ScriptableObject m_ScriptableObject;
+        PlayableAsset m_Owner;
+        static GUIContent s_GUIContent = new GUIContent();
+
+        public TimelineTrackErrorGUI(TreeViewController treeview, TimelineTreeViewGUI treeviewGUI, int id, int depth, TreeViewItem parent, string displayName, ScriptableObject track, PlayableAsset owner)
+            : base(id, depth, parent, displayName, null, treeview, treeviewGUI)
+        {
+            m_ScriptableObject = track;
+            m_Owner = owner;
+        }
+
+        public override Rect boundingRect
+        {
+            get { return m_TrackRect; }
+        }
+
+        public override bool expandable
+        {
+            get { return false; }
+        }
+
+        public override void Draw(Rect headerRect, Rect contentRect, WindowState state)
+        {
+            m_TrackRect = contentRect;
+
+            DrawMissingTrackHeader(headerRect, state);
+            DrawMissingTrackBody(contentRect);
+        }
+
+        void DrawMissingTrackHeader(Rect headerRect, WindowState state)
+        {
+            var styles = DirectorStyles.Instance;
+
+            // Draw a header
+            Color backgroundColor = styles.customSkin.colorTrackHeaderBackground;
+            var bgRect = headerRect;
+            bgRect.x += styles.trackSwatchStyle.fixedWidth;
+            bgRect.width -= styles.trackSwatchStyle.fixedWidth;
+            EditorGUI.DrawRect(bgRect, backgroundColor);
+
+            // draw the warning icon
+            var errorIcon = Styles.IconWarn;
+            Rect iconRect = new Rect(headerRect.xMin + styles.trackSwatchStyle.fixedWidth, headerRect.yMin + 0.5f * (headerRect.height - errorIcon.height), errorIcon.width, errorIcon.height);
+            if (iconRect.width > 0 && iconRect.height > 0)
+            {
+                GUI.DrawTexture(iconRect, errorIcon, ScaleMode.ScaleAndCrop, true, 0,  DirectorStyles.kClipErrorColor, 0, 0);
+            }
+
+            // Draw the name
+
+            // m_ScriptableObject == null will return true because the script can't be loaded. so this checks
+            // to make sure it is actually not null so we can grab the name
+            object o = m_ScriptableObject;
+            if (o != null)
+            {
+                s_GUIContent.text = m_ScriptableObject.name;
+                var textStyle = styles.trackHeaderFont;
+                textStyle.normal.textColor = styles.customSkin.colorTrackFont; // TODO -- we shouldn't modify the style like this. track header does it though :(
+                Rect textRect = headerRect;
+                textRect.xMin = iconRect.xMax + 1;
+                textRect.xMax = Math.Min(textRect.xMin + styles.trackHeaderFont.CalcSize(s_GUIContent).x, headerRect.xMax - 1);
+                EditorGUI.LabelField(textRect, s_GUIContent, textStyle);
+            }
+
+
+            // Draw the color swatch to the left of the track, darkened by the mute
+            var color = Color.Lerp(DirectorStyles.kClipErrorColor, styles.customSkin.colorTrackDarken, styles.customSkin.colorTrackDarken.a);
+            color.a = 1;
+            using (new GUIColorOverride(color))
+            {
+                var colorSwatchRect = headerRect;
+                colorSwatchRect.width = styles.trackSwatchStyle.fixedWidth;
+                GUI.Label(colorSwatchRect, GUIContent.none, styles.trackSwatchStyle);
+            }
+
+            // draw darken overlay
+            EditorGUI.DrawRect(bgRect, styles.customSkin.colorTrackDarken);
+
+            DrawRemoveMenu(headerRect, state);
+        }
+
+        void DrawRemoveMenu(Rect headerRect, WindowState state)
+        {
+            const float pad = 3;
+            const float buttonSize = 16;
+            var buttonRect = new Rect(headerRect.xMax - buttonSize - pad, headerRect.y + ((headerRect.height - buttonSize) / 2f) + 2, buttonSize, buttonSize);
+
+            if (GUI.Button(buttonRect, GUIContent.none, DirectorStyles.Instance.trackOptions))
+            {
+                GenericMenu menu = new GenericMenu();
+
+                var owner = m_Owner;
+                var scriptableObject = m_ScriptableObject;
+
+                menu.AddItem(Styles.RemoveTrack, false, () =>
+                {
+                    if (TrackExtensions.RemoveBrokenTrack(owner, scriptableObject))
+                        state.Refresh();
+                }
+                );
+
+                menu.ShowAsContext();
+            }
+        }
+
+        static void DrawMissingTrackBody(Rect contentRect)
+        {
+            if (contentRect.width < 0)
+                return;
+
+            var styles = DirectorStyles.Instance;
+
+            // draw a track rectangle
+            EditorGUI.DrawRect(contentRect, styles.customSkin.colorTrackDarken);
+            // draw the warning box
+            DrawScriptWarningBox(contentRect, Styles.ErrorText);
+        }
+
+        static void DrawScriptWarningBox(Rect trackRect, GUIContent content)
+        {
+            var styles = DirectorStyles.Instance;
+            const float kTextPadding = 52f;
+
+            var errorIcon = Styles.IconWarn;
+            float textWidth = styles.fontClip.CalcSize(content).x;
+
+            var outerRect = trackRect;
+            outerRect.width = textWidth + kTextPadding + errorIcon.width;
+            outerRect.x += (trackRect.width - outerRect.width) / 2f;
+            outerRect.height -= 4f;
+            outerRect.y += 1f;
+
+            bool drawText = true;
+            if (outerRect.width > trackRect.width)
+            {
+                outerRect.x = trackRect.x;
+                outerRect.width = trackRect.width;
+                drawText = false;
+            }
+
+            var innerRect = new Rect(outerRect.x + 2, outerRect.y + 2, outerRect.width - 4, outerRect.height - 4);
+            using (new GUIColorOverride(Styles.WarningBoxHighlightColor))
+                GUI.Box(outerRect, GUIContent.none, styles.displayBackground);
+            using (new GUIColorOverride(Styles.WarningBoxBackgroundColor))
+                GUI.Box(innerRect, GUIContent.none, styles.displayBackground);
+
+
+            if (drawText)
+            {
+                var iconRect = new Rect(outerRect.x + kTextPadding / 2.0f - 4.0f, outerRect.y + (outerRect.height - errorIcon.height) / 2.0f, errorIcon.width, errorIcon.height);
+                var textRect = new Rect(iconRect.xMax + 4.0f, outerRect.y, textWidth, outerRect.height);
+
+                GUI.DrawTexture(iconRect, errorIcon, ScaleMode.ScaleAndCrop, true, 0, Styles.WarningBoxHighlightColor, 0, 0);
+                Graphics.ShadowLabel(textRect, content, styles.fontClip, Color.white, Color.black);
+            }
+            else if (errorIcon.width > innerRect.width)
+            {
+                var iconRect = new Rect(outerRect.x + (outerRect.width - errorIcon.width) / 2.0f, outerRect.y + (outerRect.height - errorIcon.height) / 2.0f, errorIcon.width, errorIcon.height);
+                GUI.DrawTexture(iconRect, errorIcon, ScaleMode.ScaleAndCrop, true, 0, Styles.WarningBoxHighlightColor, 0, 0);
+            }
+        }
+
+        public override void OnGraphRebuilt() {}
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineTrackErrorGUI.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineTrackErrorGUI.cs.meta
new file mode 100644
index 0000000..dd754e2
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineTrackErrorGUI.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 200617708f5b36a4da2e2a3f1ceacedd
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineTrackGUI.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineTrackGUI.cs
new file mode 100644
index 0000000..c15d96d
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineTrackGUI.cs
@@ -0,0 +1,812 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using UnityEditor.IMGUI.Controls;
+using UnityEditor.StyleSheets;
+using UnityEngine;
+using UnityEngine.Timeline;
+using UnityEngine.Playables;
+using Object = UnityEngine.Object;
+
+namespace UnityEditor.Timeline
+{
+    class TimelineTrackGUI : TimelineGroupGUI, IClipCurveEditorOwner, IRowGUI
+    {
+        struct TrackDrawData
+        {
+            public bool                 m_AllowsRecording;
+            public bool                 m_ShowTrackBindings;
+            public bool                 m_HasBinding;
+            public bool                 m_IsSubTrack;
+            public PlayableBinding      m_Binding;
+            public UnityEngine.Object   m_TrackBinding;
+            public Texture              m_TrackIcon;
+        }
+
+        static class Styles
+        {
+            public static readonly string kArmForRecordDisabled = L10n.Tr("Recording is not permitted when Track Offsets are set to Auto. Track Offset settings can be changed in the track menu of the base track.");
+            public static Texture2D kProblemIcon = DirectorStyles.GetBackgroundImage(DirectorStyles.Instance.warning);
+        }
+
+        static GUIContent s_ArmForRecordContentOn;
+        static GUIContent s_ArmForRecordContentOff;
+        static GUIContent s_ArmForRecordDisabled;
+
+        bool m_InlineCurvesSkipped;
+        int m_TrackHash = -1;
+        int m_BlendHash = -1;
+        int m_LastDirtyIndex = -1;
+
+        readonly InfiniteTrackDrawer    m_InfiniteTrackDrawer;
+        TrackItemsDrawer                m_ItemsDrawer;
+        TrackDrawData                   m_TrackDrawData;
+        TrackDrawOptions                m_TrackDrawOptions;
+        readonly TrackEditor            m_TrackEditor;
+        readonly GUIContent             m_DefaultTrackIcon;
+
+
+        public override bool expandable
+        {
+            get { return hasChildren; }
+        }
+
+        internal InlineCurveEditor inlineCurveEditor { get; set; }
+
+        public ClipCurveEditor clipCurveEditor { get; private set; }
+
+        public bool inlineCurvesSelected
+        {
+            get { return SelectionManager.IsCurveEditorFocused(this); }
+            set
+            {
+                if (!value && SelectionManager.IsCurveEditorFocused(this))
+                    SelectionManager.SelectInlineCurveEditor(null);
+                else
+                    SelectionManager.SelectInlineCurveEditor(this);
+            }
+        }
+
+        bool IClipCurveEditorOwner.showLoops
+        {
+            get { return false; }
+        }
+
+        TrackAsset IClipCurveEditorOwner.owner
+        {
+            get { return track; }
+        }
+
+        static bool DoesTrackAllowsRecording(TrackAsset track)
+        {
+            // if the root animation track is in auto mode, recording is not allowed
+            var animTrack = TimelineUtility.GetSceneReferenceTrack(track) as AnimationTrack;
+            if (animTrack != null)
+                return animTrack.trackOffset != TrackOffset.Auto;
+
+            return false;
+        }
+
+        bool? m_TrackHasAnimatableParameters;
+        bool trackHasAnimatableParameters
+        {
+            get
+            {
+                // cache this value to avoid the recomputation
+                if (!m_TrackHasAnimatableParameters.HasValue)
+                    m_TrackHasAnimatableParameters = track.HasAnyAnimatableParameters() ||
+                        track.clips.Any(c => c.HasAnyAnimatableParameters());
+
+                return m_TrackHasAnimatableParameters.Value;
+            }
+        }
+
+        public bool locked
+        {
+            get { return track.lockedInHierarchy; }
+        }
+
+        public bool showMarkers
+        {
+            get { return track.GetShowMarkers(); }
+        }
+
+        public bool muted
+        {
+            get { return track.muted; }
+        }
+
+        public List<TimelineClipGUI> clips
+        {
+            get
+            {
+                return m_ItemsDrawer.clips == null ? new List<TimelineClipGUI>(0) : m_ItemsDrawer.clips.ToList();
+            }
+        }
+
+        TrackAsset IRowGUI.asset { get { return track; } }
+
+        bool showTrackRecordingDisabled
+        {
+            get
+            {
+                // if the root animation track is in auto mode, recording is not allowed
+                var animTrack = TimelineUtility.GetSceneReferenceTrack(track) as AnimationTrack;
+                return animTrack != null && animTrack.trackOffset == TrackOffset.Auto;
+            }
+        }
+
+        public TimelineTrackGUI(TreeViewController tv, TimelineTreeViewGUI w, int id, int depth, TreeViewItem parent, string displayName, TrackAsset sequenceActor)
+            : base(tv, w, id, depth, parent, displayName, sequenceActor, false)
+        {
+            AnimationTrack animationTrack = sequenceActor as AnimationTrack;
+            if (animationTrack != null)
+                m_InfiniteTrackDrawer = new InfiniteTrackDrawer(new AnimationTrackKeyDataSource(animationTrack));
+            else if (sequenceActor.HasAnyAnimatableParameters() && !sequenceActor.clips.Any())
+                m_InfiniteTrackDrawer = new InfiniteTrackDrawer(new TrackPropertyCurvesDataSource(sequenceActor));
+
+            UpdateInfiniteClipEditor(w.TimelineWindow);
+
+            var bindings = track.outputs.ToArray();
+            m_TrackDrawData.m_HasBinding = bindings.Length > 0;
+            if (m_TrackDrawData.m_HasBinding)
+                m_TrackDrawData.m_Binding = bindings[0];
+            m_TrackDrawData.m_IsSubTrack = IsSubTrack();
+            m_TrackDrawData.m_AllowsRecording = DoesTrackAllowsRecording(sequenceActor);
+            m_DefaultTrackIcon = TrackResourceCache.GetTrackIcon(track);
+
+
+            m_TrackEditor = CustomTimelineEditorCache.GetTrackEditor(sequenceActor);
+
+            try
+            {
+                m_TrackDrawOptions = m_TrackEditor.GetTrackOptions(track, null);
+            }
+            catch (Exception e)
+            {
+                Debug.LogException(e);
+                m_TrackDrawOptions = CustomTimelineEditorCache.GetDefaultTrackEditor().GetTrackOptions(track, null);
+            }
+
+            m_TrackDrawOptions.errorText = null; // explicitly setting to null for an uninitialized state
+
+            RebuildGUICacheIfNecessary();
+        }
+
+        public override float GetVerticalSpacingBetweenTracks()
+        {
+            if (track != null && track.isSubTrack)
+                return 1.0f; // subtracks have less of a gap than tracks
+            return base.GetVerticalSpacingBetweenTracks();
+        }
+
+        void UpdateInfiniteClipEditor(TimelineWindow window)
+        {
+            if (clipCurveEditor != null || track == null || !track.ShouldShowInfiniteClipEditor())
+                return;
+
+            var dataSource = CurveDataSource.Create(this);
+            clipCurveEditor = new ClipCurveEditor(dataSource, window, track);
+        }
+
+        void DetectTrackChanged()
+        {
+            if (Event.current.type == EventType.Layout)
+            {
+                // incremented when a track or it's clips changed
+                if (m_LastDirtyIndex != track.DirtyIndex)
+                {
+                    try
+                    {
+                        m_TrackEditor.OnTrackChanged(track);
+                    }
+                    catch (Exception e)
+                    {
+                        Debug.LogException(e);
+                    }
+                    m_LastDirtyIndex = track.DirtyIndex;
+                }
+                OnTrackChanged();
+            }
+        }
+
+        // Called when the source track data, including it's clips have changed has changed.
+        void OnTrackChanged()
+        {
+            // recompute blends if necessary
+            int newBlendHash = BlendHash();
+            if (m_BlendHash != newBlendHash)
+            {
+                UpdateClipOverlaps();
+                m_BlendHash = newBlendHash;
+            }
+
+            RebuildGUICacheIfNecessary();
+        }
+
+        void UpdateDrawData(WindowState state)
+        {
+            if (Event.current.type == EventType.Layout)
+            {
+                m_TrackDrawData.m_ShowTrackBindings = false;
+                m_TrackDrawData.m_TrackBinding = null;
+
+
+                if (state.editSequence.director != null && showSceneReference)
+                {
+                    m_TrackDrawData.m_ShowTrackBindings = state.GetWindow().currentMode.ShouldShowTrackBindings(state);
+                    m_TrackDrawData.m_TrackBinding = state.editSequence.director.GetGenericBinding(track);
+                }
+
+                var lastError = m_TrackDrawOptions.errorText;
+                var lastHeight = m_TrackDrawOptions.minimumHeight;
+                try
+                {
+                    m_TrackDrawOptions = m_TrackEditor.GetTrackOptions(track, m_TrackDrawData.m_TrackBinding);
+                }
+                catch (Exception e)
+                {
+                    Debug.LogException(e);
+                    m_TrackDrawOptions = CustomTimelineEditorCache.GetDefaultTrackEditor().GetTrackOptions(track, m_TrackDrawData.m_TrackBinding);
+                }
+
+                m_TrackDrawData.m_AllowsRecording = DoesTrackAllowsRecording(track);
+                m_TrackDrawData.m_TrackIcon = m_TrackDrawOptions.icon;
+                if (m_TrackDrawData.m_TrackIcon == null)
+                    m_TrackDrawData.m_TrackIcon = m_DefaultTrackIcon.image;
+
+                // track height has changed. need to update gui
+                if (!Mathf.Approximately(lastHeight, m_TrackDrawOptions.minimumHeight))
+                    state.Refresh();
+            }
+        }
+
+        public override void Draw(Rect headerRect, Rect contentRect, WindowState state)
+        {
+            DetectTrackChanged();
+            UpdateDrawData(state);
+
+            UpdateInfiniteClipEditor(state.GetWindow());
+
+            var trackHeaderRect = headerRect;
+            var trackContentRect = contentRect;
+
+            float inlineCurveHeight = contentRect.height - GetTrackContentHeight(state);
+            bool hasInlineCurve = inlineCurveHeight > 0.0f;
+
+            if (hasInlineCurve)
+            {
+                trackHeaderRect.height -= inlineCurveHeight;
+                trackContentRect.height -= inlineCurveHeight;
+            }
+
+            if (Event.current.type == EventType.Repaint)
+            {
+                m_TreeViewRect = trackContentRect;
+            }
+
+            if (s_ArmForRecordContentOn == null)
+                s_ArmForRecordContentOn = new GUIContent(DirectorStyles.GetBackgroundImage(DirectorStyles.Instance.autoKey, StyleState.active));
+
+            if (s_ArmForRecordContentOff == null)
+                s_ArmForRecordContentOff = new GUIContent(DirectorStyles.GetBackgroundImage(DirectorStyles.Instance.autoKey));
+
+            if (s_ArmForRecordDisabled == null)
+                s_ArmForRecordDisabled = new GUIContent(DirectorStyles.GetBackgroundImage(DirectorStyles.Instance.autoKey), Styles.kArmForRecordDisabled);
+
+            track.SetCollapsed(!isExpanded);
+
+            RebuildGUICacheIfNecessary();
+
+            // Prevents from drawing outside of bounds, but does not effect layout or markers
+            bool isOwnerDrawSucceed = false;
+
+            Vector2 visibleTime = state.timeAreaShownRange;
+
+            if (drawer != null)
+                isOwnerDrawSucceed = drawer.DrawTrack(trackContentRect, track, visibleTime, state);
+
+            if (!isOwnerDrawSucceed)
+            {
+                using (new GUIViewportScope(trackContentRect))
+                    DrawBackground(trackContentRect, track, visibleTime, state);
+
+                if (m_InfiniteTrackDrawer != null)
+                    m_InfiniteTrackDrawer.DrawTrack(trackContentRect, track, visibleTime, state);
+
+                // draw after user customization so overlay text shows up
+                using (new GUIViewportScope(trackContentRect))
+                    m_ItemsDrawer.Draw(trackContentRect, state);
+            }
+
+            DrawTrackHeader(trackHeaderRect, state);
+
+            if (hasInlineCurve)
+            {
+                var curvesHeaderRect = headerRect;
+                curvesHeaderRect.yMin = trackHeaderRect.yMax;
+
+                var curvesContentRect = contentRect;
+                curvesContentRect.yMin = trackContentRect.yMax;
+
+                DrawInlineCurves(curvesHeaderRect, curvesContentRect, state);
+            }
+
+            DrawTrackColorKind(headerRect);
+            DrawTrackState(contentRect, contentRect, track);
+        }
+
+        void DrawInlineCurves(Rect curvesHeaderRect, Rect curvesContentRect, WindowState state)
+        {
+            if (!track.GetShowInlineCurves())
+                return;
+
+            // Inline curves are not within the editor window -- case 952571
+            if (!IsInlineCurvesEditorInBounds(ToWindowSpace(curvesHeaderRect), curvesContentRect.height, state))
+            {
+                m_InlineCurvesSkipped = true;
+                return;
+            }
+
+            // If inline curves were skipped during the last event; we want to avoid rendering them until
+            // the next Layout event. Otherwise, we still get the RTE prevented above when the user resizes
+            // the timeline window very fast. -- case 952571
+            if (m_InlineCurvesSkipped && Event.current.type != EventType.Layout)
+                return;
+
+            m_InlineCurvesSkipped = false;
+
+            if (inlineCurveEditor == null)
+                inlineCurveEditor = new InlineCurveEditor(this);
+
+
+            curvesHeaderRect.x += DirectorStyles.kBaseIndent;
+            curvesHeaderRect.width -= DirectorStyles.kBaseIndent;
+
+            inlineCurveEditor.Draw(curvesHeaderRect, curvesContentRect, state);
+        }
+
+        static bool IsInlineCurvesEditorInBounds(Rect windowSpaceTrackRect, float inlineCurveHeight, WindowState state)
+        {
+            var legalHeight = state.windowHeight;
+            var trackTop = windowSpaceTrackRect.y;
+            var inlineCurveOffset = windowSpaceTrackRect.height - inlineCurveHeight;
+            return legalHeight - trackTop - inlineCurveOffset > 0;
+        }
+
+        void DrawErrorIcon(Rect position, WindowState state)
+        {
+            Rect bindingLabel = position;
+            bindingLabel.x = position.xMax + 3;
+            bindingLabel.width = state.bindingAreaWidth;
+            EditorGUI.LabelField(position, m_ProblemIcon);
+        }
+
+        void DrawBackground(Rect trackRect, TrackAsset trackAsset, Vector2 visibleTime, WindowState state)
+        {
+            bool canDrawRecordBackground = IsRecording(state);
+            if (canDrawRecordBackground)
+            {
+                DrawRecordingTrackBackground(trackRect, trackAsset, visibleTime, state);
+            }
+            else
+            {
+                Color trackBackgroundColor;
+
+                if (SelectionManager.Contains(track))
+                {
+                    trackBackgroundColor = state.IsEditingASubTimeline() ?
+                        DirectorStyles.Instance.customSkin.colorTrackSubSequenceBackgroundSelected :
+                        DirectorStyles.Instance.customSkin.colorTrackBackgroundSelected;
+                }
+                else
+                {
+                    trackBackgroundColor = state.IsEditingASubTimeline() ?
+                        DirectorStyles.Instance.customSkin.colorTrackSubSequenceBackground :
+                        DirectorStyles.Instance.customSkin.colorTrackBackground;
+                }
+
+                EditorGUI.DrawRect(trackRect, trackBackgroundColor);
+            }
+        }
+
+        float InlineCurveHeight()
+        {
+            return track.GetShowInlineCurves() && CanDrawInlineCurve()
+                ? TimelineWindowViewPrefs.GetInlineCurveHeight(track)
+                : 0.0f;
+        }
+
+        public override float GetHeight(WindowState state)
+        {
+            var height = GetTrackContentHeight(state);
+
+            if (CanDrawInlineCurve())
+                height += InlineCurveHeight();
+
+            return height;
+        }
+
+        float GetTrackContentHeight(WindowState state)
+        {
+            float height = m_TrackDrawOptions.minimumHeight;
+            if (height <= 0.0f)
+                height = TrackEditor.DefaultTrackHeight;
+            height = Mathf.Clamp(height, TrackEditor.MinimumTrackHeight, TrackEditor.MaximumTrackHeight);
+
+            return height * state.trackScale;
+        }
+
+        static bool CanDrawIcon(GUIContent icon)
+        {
+            return icon != null && icon != GUIContent.none && icon.image != null;
+        }
+
+        bool showSceneReference
+        {
+            get
+            {
+                return track != null &&
+                    m_TrackDrawData.m_HasBinding &&
+                    !m_TrackDrawData.m_IsSubTrack &&
+                    m_TrackDrawData.m_Binding.sourceObject != null &&
+                    m_TrackDrawData.m_Binding.outputTargetType != null &&
+                    typeof(Object).IsAssignableFrom(m_TrackDrawData.m_Binding.outputTargetType);
+            }
+        }
+
+        void DrawTrackHeader(Rect trackHeaderRect, WindowState state)
+        {
+            using (new GUIViewportScope(trackHeaderRect))
+            {
+                Rect rect = trackHeaderRect;
+
+                DrawHeaderBackground(trackHeaderRect);
+                rect.x += m_Styles.trackSwatchStyle.fixedWidth;
+
+                const float buttonSize = WindowConstants.trackHeaderButtonSize;
+                const float padding = WindowConstants.trackHeaderButtonPadding;
+                var buttonRect = new Rect(trackHeaderRect.xMax - buttonSize - padding, rect.y + ((rect.height - buttonSize) / 2f), buttonSize, buttonSize);
+
+                rect.x += DrawTrackIconKind(rect, state);
+                DrawTrackBinding(rect, trackHeaderRect);
+
+                if (track is GroupTrack)
+                    return;
+
+                buttonRect.x -= Spaced(DrawTrackDropDownMenu(buttonRect));
+                buttonRect.x -= Spaced(DrawLockMarkersButton(buttonRect, state));
+                buttonRect.x -= Spaced(DrawInlineCurveButton(buttonRect, state));
+                buttonRect.x -= Spaced(DrawMuteButton(buttonRect, state));
+                buttonRect.x -= Spaced(DrawLockButton(buttonRect, state));
+                buttonRect.x -= Spaced(DrawRecordButton(buttonRect, state));
+                buttonRect.x -= Spaced(DrawCustomTrackButton(buttonRect, state));
+            }
+        }
+
+        void DrawHeaderBackground(Rect headerRect)
+        {
+            Color backgroundColor = SelectionManager.Contains(track)
+                ? DirectorStyles.Instance.customSkin.colorSelection
+                : DirectorStyles.Instance.customSkin.colorTrackHeaderBackground;
+
+            var bgRect = headerRect;
+            bgRect.x += m_Styles.trackSwatchStyle.fixedWidth;
+            bgRect.width -= m_Styles.trackSwatchStyle.fixedWidth;
+
+            EditorGUI.DrawRect(bgRect, backgroundColor);
+        }
+
+        void DrawTrackColorKind(Rect rect)
+        {
+            // subtracks don't draw the color, the parent does that.
+            if (track != null && track.isSubTrack)
+                return;
+
+            if (rect.width <= 0) return;
+
+            using (new GUIColorOverride(m_TrackDrawOptions.trackColor))
+            {
+                rect.width = m_Styles.trackSwatchStyle.fixedWidth;
+                GUI.Label(rect, GUIContent.none, m_Styles.trackSwatchStyle);
+            }
+        }
+
+        float DrawTrackIconKind(Rect rect, WindowState state)
+        {
+            // no icons on subtracks
+            if (track != null && track.isSubTrack)
+                return 0.0f;
+
+            rect.yMin += (rect.height - 16f) / 2f;
+            rect.width = 16.0f;
+            rect.height = 16.0f;
+
+            if (!string.IsNullOrEmpty(m_TrackDrawOptions.errorText))
+            {
+                m_ProblemIcon.image = Styles.kProblemIcon;
+                m_ProblemIcon.tooltip = m_TrackDrawOptions.errorText;
+
+                if (CanDrawIcon(m_ProblemIcon))
+                    DrawErrorIcon(rect, state);
+            }
+            else
+            {
+                var content = GUIContent.Temp(m_TrackDrawData.m_TrackIcon, m_DefaultTrackIcon.tooltip);
+                if (CanDrawIcon(content))
+                    GUI.Box(rect, content, GUIStyle.none);
+            }
+
+            return rect.width;
+        }
+
+        void DrawTrackBinding(Rect rect, Rect headerRect)
+        {
+            if (m_TrackDrawData.m_ShowTrackBindings)
+            {
+                DoTrackBindingGUI(rect, headerRect);
+                return;
+            }
+
+            var textStyle = m_Styles.trackHeaderFont;
+            textStyle.normal.textColor = SelectionManager.Contains(track) ? Color.white : m_Styles.customSkin.colorTrackFont;
+
+            string trackName = track.name;
+
+            EditorGUI.BeginChangeCheck();
+
+            // by default the size is just the width of the string (for selection purposes)
+            rect.width = m_Styles.trackHeaderFont.CalcSize(new GUIContent(trackName)).x;
+
+            // if we are editing, supply the entire width of the header
+            if (GUIUtility.keyboardControl == track.GetInstanceID())
+                rect.width = (headerRect.xMax - rect.xMin) - (5 * WindowConstants.trackHeaderButtonSize);
+
+            trackName = EditorGUI.DelayedTextField(rect, GUIContent.none, track.GetInstanceID(), track.name, textStyle);
+
+            if (EditorGUI.EndChangeCheck())
+            {
+                TimelineUndo.PushUndo(track, "Rename Track");
+                track.name = trackName;
+            }
+        }
+
+        float DrawTrackDropDownMenu(Rect rect)
+        {
+            rect.y += WindowConstants.trackOptionButtonVerticalPadding;
+
+            if (GUI.Button(rect, GUIContent.none, m_Styles.trackOptions))
+            {
+                // the drop down will apply to all selected tracks
+                if (!SelectionManager.Contains(track))
+                {
+                    SelectionManager.Clear();
+                    SelectionManager.Add(track);
+                }
+
+                SequencerContextMenu.ShowTrackContextMenu(SelectionManager.SelectedTracks().ToArray(), null);
+            }
+
+            return WindowConstants.trackHeaderButtonSize;
+        }
+
+        bool CanDrawInlineCurve()
+        {
+            // Note: A track with animatable parameters always has inline curves.
+            return trackHasAnimatableParameters || TimelineUtility.TrackHasAnimationCurves(track);
+        }
+
+        float DrawInlineCurveButton(Rect rect, WindowState state)
+        {
+            if (!CanDrawInlineCurve())
+            {
+                return 0.0f;
+            }
+
+            // Override enable state to display "Show Inline Curves" button in disabled state.
+            bool prevEnabledState = GUI.enabled;
+            GUI.enabled = true;
+            var newValue = GUI.Toggle(rect, track.GetShowInlineCurves(), GUIContent.none, DirectorStyles.Instance.curves);
+            GUI.enabled = prevEnabledState;
+
+            if (newValue != track.GetShowInlineCurves())
+            {
+                track.SetShowInlineCurves(newValue);
+                state.GetWindow().treeView.CalculateRowRects();
+            }
+
+            return WindowConstants.trackHeaderButtonSize;
+        }
+
+        float DrawRecordButton(Rect rect, WindowState state)
+        {
+            if (m_TrackDrawData.m_AllowsRecording)
+            {
+                bool isPlayerDisabled = state.editSequence.director != null && !state.editSequence.director.isActiveAndEnabled;
+
+                GameObject goBinding = m_TrackDrawData.m_TrackBinding as GameObject;
+                if (goBinding == null)
+                {
+                    Component c = m_TrackDrawData.m_TrackBinding as Component;
+                    if (c != null)
+                        goBinding = c.gameObject;
+                }
+
+                if (goBinding == null && m_TrackDrawData.m_IsSubTrack)
+                {
+                    goBinding = ParentTrack().GetGameObjectBinding(state.editSequence.director);
+                }
+
+                bool isTrackBindingValid = goBinding != null;
+                bool trackErrorDisableButton = !string.IsNullOrEmpty(m_TrackDrawOptions.errorText) && isTrackBindingValid && goBinding.activeInHierarchy;
+                bool disableButton = track.lockedInHierarchy || isPlayerDisabled || trackErrorDisableButton || !isTrackBindingValid;
+                using (new EditorGUI.DisabledScope(disableButton))
+                {
+                    if (IsRecording(state))
+                    {
+                        state.editorWindow.Repaint();
+                        float remainder = Time.realtimeSinceStartup % 1;
+
+                        var animatedContent = s_ArmForRecordContentOn;
+                        if (remainder < 0.22f)
+                        {
+                            animatedContent = GUIContent.none;
+                        }
+                        if (GUI.Button(rect, animatedContent, GUIStyle.none) || isPlayerDisabled || !isTrackBindingValid)
+                        {
+                            state.UnarmForRecord(track);
+                        }
+                    }
+                    else
+                    {
+                        if (GUI.Button(rect, s_ArmForRecordContentOff, GUIStyle.none))
+                        {
+                            state.ArmForRecord(track);
+                        }
+                    }
+                    return WindowConstants.trackHeaderButtonSize;
+                }
+            }
+
+            if (showTrackRecordingDisabled)
+            {
+                using (new EditorGUI.DisabledScope(true))
+                    GUI.Button(rect, s_ArmForRecordDisabled, GUIStyle.none);
+                return k_ButtonSize;
+            }
+
+            return 0.0f;
+        }
+
+        float DrawCustomTrackButton(Rect rect, WindowState state)
+        {
+            if (drawer.DrawTrackHeaderButton(rect, track, state))
+            {
+                return WindowConstants.trackHeaderButtonSize;
+            }
+            return 0.0f;
+        }
+
+        float DrawLockMarkersButton(Rect rect, WindowState state)
+        {
+            if (track.GetMarkerCount() == 0)
+                return 0.0f;
+
+            var markersShown = showMarkers;
+            var style = TimelineWindow.styles.collapseMarkers;
+            if (Event.current.type == EventType.Repaint)
+                style.Draw(rect, GUIContent.none, false, false, markersShown, false);
+
+            // Override enable state to display "Show Marker" button in disabled state.
+            bool prevEnabledState = GUI.enabled;
+            GUI.enabled = true;
+            if (GUI.Button(rect, DirectorStyles.markerCollapseButton, GUIStyle.none))
+            {
+                state.GetWindow().SetShowTrackMarkers(track, !markersShown);
+            }
+            GUI.enabled = prevEnabledState;
+            return WindowConstants.trackHeaderButtonSize;
+        }
+
+        static void ObjectBindingField(Rect position, Object obj, PlayableBinding binding)
+        {
+            bool allowScene =
+                typeof(GameObject).IsAssignableFrom(binding.outputTargetType) ||
+                typeof(Component).IsAssignableFrom(binding.outputTargetType);
+
+            using (var check = new EditorGUI.ChangeCheckScope())
+            {
+                // FocusType.Passive so it never gets focused when pressing tab
+                int controlId = GUIUtility.GetControlID("s_ObjectFieldHash".GetHashCode(), FocusType.Passive, position);
+                var newObject = UnityEditorInternals.DoObjectField(EditorGUI.IndentedRect(position), obj, binding.outputTargetType, controlId, allowScene);
+                if (check.changed)
+                {
+                    BindingUtility.Bind(TimelineEditor.inspectedDirector, binding.sourceObject as TrackAsset, newObject);
+                }
+            }
+        }
+
+        void DoTrackBindingGUI(Rect rect, Rect headerRect)
+        {
+            var bindingRect = new Rect(
+                rect.xMin,
+                rect.y + (rect.height - WindowConstants.trackHeaderButtonSize) / 2f,
+                headerRect.xMax - WindowConstants.trackHeaderMaxButtonsWidth - rect.xMin,
+                WindowConstants.trackHeaderButtonSize);
+
+            if (bindingRect.Contains(Event.current.mousePosition) && TimelineDragging.IsDraggingEvent() && DragAndDrop.objectReferences.Length == 1)
+            {
+                TimelineDragging.HandleBindingDragAndDrop(track, BindingUtility.GetRequiredBindingType(m_TrackDrawData.m_Binding));
+                Event.current.Use();
+            }
+            else
+            {
+                if (m_TrackDrawData.m_Binding.outputTargetType != null && typeof(Object).IsAssignableFrom(m_TrackDrawData.m_Binding.outputTargetType))
+                {
+                    ObjectBindingField(bindingRect, m_TrackDrawData.m_TrackBinding, m_TrackDrawData.m_Binding);
+                }
+            }
+        }
+
+        bool IsRecording(WindowState state)
+        {
+            return state.recording && state.IsArmedForRecord(track);
+        }
+
+        // background to draw during recording
+        void DrawRecordingTrackBackground(Rect trackRect, TrackAsset trackAsset, Vector2 visibleTime, WindowState state)
+        {
+            if (drawer != null)
+                drawer.DrawRecordingBackground(trackRect, trackAsset, visibleTime, state);
+        }
+
+        void UpdateClipOverlaps()
+        {
+            TrackExtensions.ComputeBlendsFromOverlaps(track.clips);
+        }
+
+        internal void RebuildGUICacheIfNecessary()
+        {
+            if (m_TrackHash == track.Hash())
+                return;
+
+            m_ItemsDrawer = new TrackItemsDrawer(this);
+            m_TrackHash = track.Hash();
+        }
+
+        int BlendHash()
+        {
+            var hash = 0;
+            foreach (var clip in track.clips)
+            {
+                hash = HashUtility.CombineHash(hash,
+                    (clip.duration - clip.start).GetHashCode(),
+                    ((int)clip.blendInCurveMode).GetHashCode(),
+                    ((int)clip.blendOutCurveMode).GetHashCode());
+            }
+            return hash;
+        }
+
+        // callback when the corresponding graph is rebuilt. This can happen, but not have the GUI rebuilt.
+        public override void OnGraphRebuilt()
+        {
+            RefreshCurveEditor();
+        }
+
+        void RefreshCurveEditor()
+        {
+            var window = TimelineWindow.instance;
+            if (track != null && window != null && window.state != null)
+            {
+                bool hasEditor = clipCurveEditor != null;
+                bool shouldHaveEditor = track.ShouldShowInfiniteClipEditor();
+                if (hasEditor != shouldHaveEditor)
+                    window.state.AddEndFrameDelegate((x, currentEvent) =>
+                    {
+                        x.Refresh();
+                        return true;
+                    });
+            }
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineTrackGUI.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineTrackGUI.cs.meta
new file mode 100644
index 0000000..bff54b9
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineTrackGUI.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 468e1bfc887161e4196f33e942fc3199
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineTreeView.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineTreeView.cs
new file mode 100644
index 0000000..9345d9a
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineTreeView.cs
@@ -0,0 +1,439 @@
+using System.Collections.Generic;
+using System.Linq;
+using UnityEditor.IMGUI.Controls;
+using UnityEngine;
+
+namespace UnityEditor.Timeline
+{
+    class TimelineTreeView : ITreeViewGUI
+    {
+        float m_FoldoutWidth;
+        Rect m_DraggingInsertionMarkerRect;
+        readonly TreeViewController m_TreeView;
+
+        List<Rect> m_RowRects = new List<Rect>();
+        List<Rect> m_ExpandedRowRects = new List<Rect>();
+
+        float m_MaxWidthOfRows;
+        readonly WindowState m_State;
+
+        static readonly float kMinTrackHeight = 25.0f;
+        static readonly float kFoldOutOffset = 14.0f;
+
+        static DirectorStyles m_Styles;
+
+        public bool showInsertionMarker { get; set; }
+        public virtual float topRowMargin { get; private set; }
+        public virtual float bottomRowMargin { get; private set; }
+
+        public TimelineTreeView(TimelineWindow sequencerWindow, TreeViewController treeView)
+        {
+            m_TreeView = treeView;
+            m_TreeView.useExpansionAnimation = true;
+
+            m_TreeView.selectionChangedCallback += SelectionChangedCallback;
+            m_TreeView.contextClickOutsideItemsCallback += ContextClickOutsideItemsCallback;
+            m_TreeView.itemDoubleClickedCallback += ItemDoubleClickedCallback;
+            m_TreeView.contextClickItemCallback += ContextClickItemCallback;
+
+            m_TreeView.SetConsumeKeyDownEvents(false);
+            m_Styles = DirectorStyles.Instance;
+            m_State = sequencerWindow.state;
+
+            m_FoldoutWidth = DirectorStyles.Instance.foldout.fixedWidth;
+        }
+
+        void ItemDoubleClickedCallback(int id)
+        {
+            var trackGUI = m_TreeView.FindItem(id) as TimelineTrackGUI;
+            if (trackGUI == null)
+                return;
+
+            if (trackGUI.track == null || trackGUI.track.lockedInHierarchy)
+                return;
+
+            var selection = SelectionManager.SelectedItems().ToList();
+            var items = ItemsUtils.GetItems(trackGUI.track).ToList();
+            var addToSelection = !selection.SequenceEqual(items);
+
+            foreach (var i in items)
+            {
+                if (addToSelection)
+                    SelectionManager.Add(i);
+                else
+                    SelectionManager.Remove(i);
+            }
+        }
+
+        void ContextClickOutsideItemsCallback()
+        {
+            SequencerContextMenu.ShowNewTracksContextMenu(null, m_State);
+            Event.current.Use();
+        }
+
+        void ContextClickItemCallback(int id)
+        {
+            // may not occur if another menu is active
+            if (!m_TreeView.IsSelected(id))
+                SelectionChangedCallback(new[] {id});
+
+            SequencerContextMenu.ShowTrackContextMenu(SelectionManager.SelectedTracks().ToArray(), Event.current.mousePosition);
+
+            Event.current.Use();
+        }
+
+        void SelectionChangedCallback(int[] ids)
+        {
+            if (Event.current.button == 1 && PickerUtils.PickedLayerableOfType<ISelectable>() != null)
+                return;
+
+            if (Event.current.command || Event.current.control || Event.current.shift)
+                SelectionManager.UnSelectTracks();
+            else
+                SelectionManager.Clear();
+
+            foreach (var id in ids)
+            {
+                var trackGUI = (TimelineTrackBaseGUI)m_TreeView.FindItem(id);
+                SelectionManager.Add(trackGUI.track);
+            }
+
+            m_State.GetWindow().Repaint();
+        }
+
+        public void OnInitialize() {}
+
+        public Rect GetRectForFraming(int row)
+        {
+            return GetRowRect(row, 1); // We ignore width by default when framing (only y scroll is affected)
+        }
+
+        protected virtual Vector2 GetSizeOfRow(TreeViewItem item)
+        {
+            if (item.displayName == "root")
+                return new Vector2(m_TreeView.GetTotalRect().width, 0.0f);
+
+            var trackGroupGui = item as TimelineGroupGUI;
+            if (trackGroupGui != null)
+            {
+                return new Vector2(m_TreeView.GetTotalRect().width, trackGroupGui.GetHeight(m_State));
+            }
+
+            float height = TrackEditor.DefaultTrackHeight;
+            if (item.hasChildren && m_TreeView.data.IsExpanded(item))
+            {
+                height = Mathf.Min(TrackEditor.DefaultTrackHeight, kMinTrackHeight);
+            }
+
+            return new Vector2(m_TreeView.GetTotalRect().width, height);
+        }
+
+        public virtual void BeginRowGUI()
+        {
+            if (m_TreeView.GetTotalRect().width != GetRowRect(0).width)
+            {
+                CalculateRowRects();
+            }
+
+            m_DraggingInsertionMarkerRect.x = -1;
+
+            m_TreeView.SetSelection(SelectionManager.SelectedTrackGUI().Select(t => t.id).ToArray(), false);
+        }
+
+        public virtual void EndRowGUI()
+        {
+            // Draw row marker when dragging
+            if (m_DraggingInsertionMarkerRect.x >= 0 && Event.current.type == EventType.Repaint)
+            {
+                Rect insertionRect = m_DraggingInsertionMarkerRect;
+                const float insertionHeight = 1.0f;
+                insertionRect.height = insertionHeight;
+
+                if (m_TreeView.dragging.drawRowMarkerAbove)
+                    insertionRect.y -= insertionHeight * 0.5f + 2.0f;
+                else
+                    insertionRect.y += m_DraggingInsertionMarkerRect.height - insertionHeight * 0.5f + 1.0f;
+
+                EditorGUI.DrawRect(insertionRect, Color.white);
+            }
+        }
+
+        public virtual void OnRowGUI(Rect rowRect, TreeViewItem item, int row, bool selected, bool focused)
+        {
+            using (new EditorGUI.DisabledScope(TimelineWindow.instance.currentMode.TrackState(TimelineWindow.instance.state) == TimelineModeGUIState.Disabled))
+            {
+                var sqvi = (TimelineTrackBaseGUI)item;
+                sqvi.treeViewToWindowTransformation = m_TreeView.GetTotalRect().position - m_TreeView.state.scrollPos;
+
+                // this may be called because an encompassing parent is visible
+                if (!sqvi.visibleExpanded)
+                    return;
+
+                Rect headerRect = rowRect;
+                Rect contentRect = rowRect;
+
+                headerRect.width = m_State.sequencerHeaderWidth - 2.0f;
+                contentRect.xMin += m_State.sequencerHeaderWidth;
+                contentRect.width = rowRect.width - m_State.sequencerHeaderWidth - 1.0f;
+
+                Rect foldoutRect = rowRect;
+
+                var indent = GetFoldoutIndent(item);
+                var headerRectWithIndent = headerRect;
+                headerRectWithIndent.xMin = indent;
+                var rowRectWithIndent = new Rect(rowRect.x + indent, rowRect.y, rowRect.width - indent, rowRect.height);
+                sqvi.Draw(headerRectWithIndent, contentRect, m_State);
+                sqvi.DrawInsertionMarkers(rowRectWithIndent);
+
+                if (Event.current.type == EventType.Repaint)
+                {
+                    m_State.spacePartitioner.AddBounds(sqvi);
+
+                    // Show marker below this Item
+                    if (showInsertionMarker)
+                    {
+                        if (m_TreeView.dragging != null && m_TreeView.dragging.GetRowMarkerControlID() == TreeViewController.GetItemControlID(item))
+                            m_DraggingInsertionMarkerRect = rowRectWithIndent;
+                    }
+                }
+
+                // Draw foldout (after text content above to ensure drop down icon is rendered above selection highlight)
+                DrawFoldout(item, foldoutRect, indent);
+
+                sqvi.ClearDrawFlags();
+            }
+        }
+
+        void DrawFoldout(TreeViewItem item, Rect foldoutRect, float indent)
+        {
+            var showFoldout = m_TreeView.data.IsExpandable(item);
+            if (showFoldout)
+            {
+                foldoutRect.x = indent - kFoldOutOffset;
+                foldoutRect.width = m_FoldoutWidth;
+                EditorGUI.BeginChangeCheck();
+                float foldoutIconHeight = DirectorStyles.Instance.foldout.fixedHeight;
+                foldoutRect.y += foldoutIconHeight / 2.0f;
+                foldoutRect.height = foldoutIconHeight;
+
+                if (foldoutRect.xMax > m_State.sequencerHeaderWidth)
+                    return;
+
+                //Override Disable state for TrakGroup toggle button to expand/collapse group.
+                bool previousEnableState = GUI.enabled;
+                GUI.enabled = true;
+                bool newExpandedValue = GUI.Toggle(foldoutRect, m_TreeView.data.IsExpanded(item), GUIContent.none, m_Styles.foldout);
+                GUI.enabled = previousEnableState;
+
+                if (EditorGUI.EndChangeCheck())
+                {
+                    if (Event.current.alt)
+                        m_TreeView.data.SetExpandedWithChildren(item, newExpandedValue);
+                    else
+                        m_TreeView.data.SetExpanded(item, newExpandedValue);
+                }
+            }
+        }
+
+        public Rect GetRenameRect(Rect rowRect, int row, TreeViewItem item)
+        {
+            return rowRect;
+        }
+
+        public void BeginPingItem(TreeViewItem item, float topPixelOfRow, float availableWidth) {}
+        public void EndPingItem() {}
+
+        public Rect GetRowRect(int row,  float rowWidth)
+        {
+            return GetRowRect(row);
+        }
+
+        public Rect GetRowRect(int row)
+        {
+            if (m_RowRects.Count == 0)
+                return new Rect();
+
+            if (row >= m_RowRects.Count)
+                return new Rect();
+
+            return m_RowRects[row];
+        }
+
+        static float GetSpacing(TreeViewItem item)
+        {
+            var trackBase = item as TimelineTrackBaseGUI;
+            if (trackBase != null)
+                return trackBase.GetVerticalSpacingBetweenTracks();
+
+            return 3.0f;
+        }
+
+        public void CalculateRowRects()
+        {
+            if (m_TreeView.isSearching)
+                return;
+
+            const float startY = 6.0f;
+            IList<TreeViewItem> rows = m_TreeView.data.GetRows();
+            m_RowRects = new List<Rect>(rows.Count);
+            m_ExpandedRowRects = new List<Rect>(rows.Count);
+
+            float curY = startY;
+            m_MaxWidthOfRows = 1f;
+
+            // first pass compute the row rects
+            for (int i = 0; i < rows.Count; ++i)
+            {
+                var item = rows[i];
+
+                if (i != 0)
+                    curY += GetSpacing(item);
+
+                Vector2 rowSize = GetSizeOfRow(item);
+                m_RowRects.Add(new Rect(0, curY, rowSize.x, rowSize.y));
+                m_ExpandedRowRects.Add(m_RowRects[i]);
+
+                curY += rowSize.y;
+
+                if (rowSize.x > m_MaxWidthOfRows)
+                    m_MaxWidthOfRows = rowSize.x;
+
+                // updated the expanded state
+                var groupGUI = item as TimelineGroupGUI;
+                if (groupGUI != null)
+                    groupGUI.SetExpanded(m_TreeView.data.IsExpanded(item));
+            }
+
+            float halfHeight = halfDropBetweenHeight;
+            const float kGroupPad = 1.0f;
+            const float kSkinPadding = 5.0f * 0.6f;
+            // work bottom up and compute visible regions for groups
+            for (int i = rows.Count - 1; i > 0; i--)
+            {
+                float height = 0;
+                TimelineTrackBaseGUI item = (TimelineTrackBaseGUI)rows[i];
+                if (item.isExpanded && item.children != null && item.children.Count > 0)
+                {
+                    for (var j = 0; j < item.children.Count; j++)
+                    {
+                        var child = item.children[j];
+                        int index = rows.IndexOf(child);
+                        if (index > i)
+                            height += m_ExpandedRowRects[index].height + kSkinPadding;
+                    }
+
+                    height += kGroupPad;
+                }
+                m_ExpandedRowRects[i] = new Rect(m_RowRects[i].x, m_RowRects[i].y, m_RowRects[i].width, m_RowRects[i].height + height);
+
+                var groupGUI = item as TimelineGroupGUI;
+                if (groupGUI != null)
+                {
+                    var spacing = GetSpacing(item) + 1;
+                    groupGUI.expandedRect = m_ExpandedRowRects[i];
+                    groupGUI.rowRect = m_RowRects[i];
+                    groupGUI.dropRect = new Rect(m_RowRects[i].x, m_RowRects[i].y - spacing, m_RowRects[i].width, m_RowRects[i].height + Mathf.Max(halfHeight, spacing));
+                }
+            }
+        }
+
+        public virtual bool BeginRename(TreeViewItem item, float delay)
+        {
+            return false;
+        }
+
+        public virtual void EndRename() {}
+
+        protected virtual float GetFoldoutIndent(TreeViewItem item)
+        {
+            // Ignore depth when showing search results
+            if (item.depth <= 1 || m_TreeView.isSearching)
+                return DirectorStyles.kBaseIndent;
+
+            int depth = item.depth;
+            var trackGUI = item as TimelineTrackGUI;
+
+            // first level subtracks are not indented
+            if (trackGUI != null && trackGUI.track != null && trackGUI.track.isSubTrack)
+                depth--;
+
+            return depth * DirectorStyles.kBaseIndent;
+        }
+
+        public virtual float GetContentIndent(TreeViewItem item)
+        {
+            return GetFoldoutIndent(item);
+        }
+
+        public int GetNumRowsOnPageUpDown(TreeViewItem fromItem, bool pageUp, float heightOfTreeView)
+        {
+            return (int)Mathf.Floor(heightOfTreeView / 30); // return something
+        }
+
+        // Should return the row number of the first and last row thats fits in the pixel rect defined by top and height
+        public void GetFirstAndLastRowVisible(out int firstRowVisible, out int lastRowVisible)
+        {
+            int rowCount = m_TreeView.data.rowCount;
+            if (rowCount == 0)
+            {
+                firstRowVisible = lastRowVisible = -1;
+                return;
+            }
+
+            if (rowCount != m_ExpandedRowRects.Count)
+            {
+                Debug.LogError("Mismatch in state: rows vs cached rects. Did you remember to hook up: dataSource.onVisibleRowsChanged += gui.CalculateRowRects ?");
+                CalculateRowRects();
+            }
+
+            float topPixel = m_TreeView.state.scrollPos.y;
+            float heightInPixels = m_TreeView.GetTotalRect().height;
+
+            int firstVisible = -1;
+            int lastVisible = -1;
+
+            Rect visibleRect = new Rect(0, topPixel, m_ExpandedRowRects[0].width, heightInPixels);
+            for (int i = 0; i < m_ExpandedRowRects.Count; ++i)
+            {
+                bool visible = visibleRect.Overlaps(m_ExpandedRowRects[i]);
+                if (visible)
+                {
+                    if (firstVisible == -1)
+                        firstVisible = i;
+                    lastVisible = i;
+                }
+
+                TimelineTrackBaseGUI gui = m_TreeView.data.GetItem(i) as TimelineTrackBaseGUI;
+                if (gui != null)
+                {
+                    gui.visibleExpanded = visible;
+                    gui.visibleRow = visibleRect.Overlaps(m_RowRects[i]);
+                }
+            }
+
+            if (firstVisible != -1 && lastVisible != -1)
+            {
+                firstRowVisible = firstVisible;
+                lastRowVisible = lastVisible;
+            }
+            else
+            {
+                firstRowVisible = 0;
+                lastRowVisible = rowCount - 1;
+            }
+        }
+
+        public Vector2 GetTotalSize()
+        {
+            if (m_RowRects.Count == 0)
+                return new Vector2(0, 0);
+
+            return new Vector2(m_MaxWidthOfRows, m_RowRects[m_RowRects.Count - 1].yMax);
+        }
+
+        public virtual float halfDropBetweenHeight
+        {
+            get { return 8f; }
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineTreeView.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineTreeView.cs.meta
new file mode 100644
index 0000000..a555d92
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineTreeView.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 82a8ce43816925d4b971951094cb755c
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineTreeViewGUI.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineTreeViewGUI.cs
new file mode 100644
index 0000000..6160a35
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineTreeViewGUI.cs
@@ -0,0 +1,182 @@
+using System.Collections.Generic;
+using System.Linq;
+using UnityEditor.IMGUI.Controls;
+using UnityEngine;
+using UnityEngine.Timeline;
+
+namespace UnityEditor.Timeline
+{
+    class TimelineTreeViewGUI
+    {
+        readonly TimelineAsset m_Timeline;
+        readonly TreeViewController m_TreeView;
+        readonly TimelineTreeView m_TimelineTreeView;
+        readonly TimelineWindow m_Window;
+        readonly TimelineDataSource m_DataSource;
+
+        TreeViewItem root
+        {
+            get { return m_DataSource.root; }
+        }
+
+        TimelineTrackBaseGUI[] visibleTrackGuis
+        {
+            get
+            {
+                int firstRow;
+                int lastRow;
+                var visibleRows = new List<TimelineTrackBaseGUI>();
+                m_TreeView.gui.GetFirstAndLastRowVisible(out firstRow, out lastRow);
+
+                for (int r = firstRow; r <= lastRow; r++)
+                {
+                    var track = m_TreeView.data.GetItem(r) as TimelineTrackBaseGUI;
+                    if (track != null && track != root)
+                    {
+                        AddVisibleTrackRecursive(ref visibleRows, track);
+                    }
+                }
+                return visibleRows.ToArray();
+            }
+        }
+
+        public TrackAsset[] visibleTracks
+        {
+            get { return visibleTrackGuis.Select(x => x.track).ToArray(); }
+        }
+
+        public List<TimelineClipGUI> allClipGuis
+        {
+            get
+            {
+                TimelineDataSource dataSource = m_TreeView.data as TimelineDataSource;
+                if (dataSource != null && dataSource.allTrackGuis != null)
+                    return dataSource.allTrackGuis.OfType<TimelineTrackGUI>().SelectMany(x => x.clips).ToList();
+
+                return null;
+            }
+        }
+
+        public List<TimelineTrackBaseGUI> allTrackGuis
+        {
+            get
+            {
+                var dataSource = m_TreeView.data as TimelineDataSource;
+                if (dataSource != null)
+                    return dataSource.allTrackGuis;
+                return null;
+            }
+        }
+
+        public Vector2 contentSize
+        {
+            get { return m_TreeView.GetContentSize(); }
+        }
+
+        public Vector2 scrollPosition
+        {
+            get { return m_TreeView.state.scrollPos; }
+            set
+            {
+                Rect r = m_TreeView.GetTotalRect();
+                Vector2 visibleContent = m_TreeView.GetContentSize();
+                m_TreeView.state.scrollPos = new Vector2(value.x, Mathf.Clamp(value.y, 0, Mathf.Max(0, visibleContent.y - r.height)));
+            }
+        }
+
+        public bool showingVerticalScrollBar
+        {
+            get { return m_TreeView.showingVerticalScrollBar; }
+        }
+
+        public void FrameItem(TreeViewItem item)
+        {
+            m_TreeView.Frame(item.id, true, false, true);
+        }
+
+        public TimelineDragging timelineDragging { get {return m_TreeView.dragging as TimelineDragging; }}
+
+        public TimelineTreeViewGUI(TimelineWindow sequencerWindow, TimelineAsset timeline,  Rect rect)
+        {
+            m_Timeline = timeline;
+            m_Window = sequencerWindow;
+
+            var treeviewState = new TreeViewState();
+            treeviewState.scrollPos = new Vector2(treeviewState.scrollPos.x, TimelineWindowViewPrefs.GetOrCreateViewModel(m_Timeline).verticalScroll);
+
+            m_TreeView = new TreeViewController(sequencerWindow, treeviewState);
+            m_TreeView.horizontalScrollbarStyle = GUIStyle.none;
+            m_TreeView.scrollViewStyle = GUI.skin.scrollView;
+            m_TreeView.keyboardInputCallback = sequencerWindow.TreeViewKeyboardCallback;
+
+
+            m_TimelineTreeView = new TimelineTreeView(sequencerWindow, m_TreeView);
+            var dragging = new TimelineDragging(m_TreeView, m_Window, m_Timeline);
+            m_DataSource = new TimelineDataSource(this, m_TreeView, sequencerWindow);
+
+            m_DataSource.onVisibleRowsChanged += m_TimelineTreeView.CalculateRowRects;
+            m_TreeView.Init(rect, m_DataSource, m_TimelineTreeView, dragging);
+
+            m_DataSource.ExpandItems(m_DataSource.root);
+        }
+
+        public ITreeViewGUI gui
+        {
+            get { return m_TimelineTreeView; }
+        }
+        public ITreeViewDataSource data
+        {
+            get { return m_TreeView == null ? null : m_TreeView.data; }
+        }
+
+        public TimelineWindow TimelineWindow
+        {
+            get { return m_Window; }
+        }
+
+        public void CalculateRowRects()
+        {
+            m_TimelineTreeView.CalculateRowRects();
+        }
+
+        public void Reload()
+        {
+            AnimationClipCurveCache.Instance.ClearCachedProxyClips();
+
+            m_TreeView.ReloadData();
+            m_DataSource.ExpandItems(m_DataSource.root);
+            m_TimelineTreeView.CalculateRowRects();
+        }
+
+        public void OnGUI(Rect rect)
+        {
+            int keyboardControl = GUIUtility.GetControlID(FocusType.Passive, rect);
+            m_TreeView.OnGUI(rect, keyboardControl);
+            TimelineWindowViewPrefs.GetOrCreateViewModel(m_Timeline).verticalScroll = m_TreeView.state.scrollPos.y;
+        }
+
+        public Rect GetRowRect(int row)
+        {
+            return m_TimelineTreeView.GetRowRect(row);
+        }
+
+        static void AddVisibleTrackRecursive(ref List<TimelineTrackBaseGUI> list, TimelineTrackBaseGUI track)
+        {
+            if (track == null)
+                return;
+
+            list.Add(track);
+
+            if (!track.isExpanded)
+                return;
+
+            if (track.children != null)
+            {
+                foreach (var c in track.children)
+                {
+                    AddVisibleTrackRecursive(ref list, c as TimelineTrackBaseGUI);
+                }
+            }
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineTreeViewGUI.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineTreeViewGUI.cs.meta
new file mode 100644
index 0000000..7363134
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TimelineTreeViewGUI.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: f9d8c8b21846a654092a24f25aa41421
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TrackPropertyCurvesDataSource.cs b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TrackPropertyCurvesDataSource.cs
new file mode 100644
index 0000000..4b808ea
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TrackPropertyCurvesDataSource.cs
@@ -0,0 +1,15 @@
+using UnityEngine;
+using UnityEngine.Timeline;
+
+namespace UnityEditor.Timeline
+{
+    class TrackPropertyCurvesDataSource : BasePropertyKeyDataSource
+    {
+        protected override AnimationClip animationClip { get; }
+
+        public TrackPropertyCurvesDataSource(TrackAsset track)
+        {
+            animationClip = track != null ? track.curves : null;
+        }
+    }
+}
diff --git a/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TrackPropertyCurvesDataSource.cs.meta b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TrackPropertyCurvesDataSource.cs.meta
new file mode 100644
index 0000000..fc351b4
--- /dev/null
+++ b/Library/PackageCache/com.unity.timeline@1.2.13/Editor/treeview/TrackPropertyCurvesDataSource.cs.meta
@@ -0,0 +1,11 @@
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