private boolean insideTreeItemsArea(MouseEvent e) {
      Rectangle rowBounds = getRowBounds(getRowCount() - 1);
      if (rowBounds == null) {
        return false;
      }
      double lastItemBottomLine = rowBounds.getMaxY();
      return e.getY() <= lastItemBottomLine;
    }
private boolean insideTreeItemsArea(MouseEvent e)