@Override
    public void invokePopup(Component comp, int x, int y) {
      JScrollPane scrollPane = (JScrollPane)comp;
      PaletteContentWindow contentWindow = (PaletteContentWindow)scrollPane.getViewport().getView();
      if (contentWindow != null) {
        PaletteGroupHeader groupHeader = contentWindow.getLastGroupHeader();
        if (groupHeader != null) {
          groupHeader.showGroupPopupMenu(comp, x, y);
        }
      }
    }
@Override
    public void invokePopup(Component comp, int x, int y)