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);
}