anchor.diff:      _listView = new ListView(element, this);
       _rows = null;
       _rowsMap = null;
  +    _pendingExpansionTimer = null;
  +    _pendingExpansionUID = null;
       reloadData();
     }
   
  
positive.code:   TreeViewCell _currentDragOverCell;
    // Whether the user can drag a cell.
    bool draggingEnabled = false;
    // Unique identifier of the tree.
    String _uuid;
  
  
negative.code:       }
        if (cell != null) {
          cell.dragOverlayVisible = true;
          
          if(_pendingExpansionUID != cell.nodeUID) {
            if(_pendingExpansionTimer != null) {
              _pendingExpansionTimer.cancel();
            }
          }
          //queue cell for expanding if it's a pausing drag hover
          _pendingExpansionUID = cell.nodeUID;
          _pendingExpansionTimer = new Timer(const Duration(milliseconds: 1000), () {
            if(_currentDragOverCell != null) {
              if(nodeUID == _currentDragOverCell.nodeUID) {
                if(!isNodeExpanded(nodeUID)) {
  