code: protected void reset ()
      {
          _scrollTimer.stop();
  
          _source = null;
          _sourceComp = null;
          _lastComp = null;
          _lastTarget = null;
          _data[0] = null;
          _cursors[0] = null;
          _cursors[1] = null;
          _topComp = null;
          _topCursor = null;
          _curCursor = null;
  
          _scrollComp = null;
          _scrollDim = null;
          _scrollPoint = null;
      }
docs: Reset dnd to a starting state.