/** ***************************************************************************** */
  @Override
  public void handlePopupMenu(MouseEvent e) {
    JPopupMenu popup = new JPopupMenu();
    Point pt = SwingUtilities.convertPoint(getContentPane().getParent(), e.getPoint(), draw_area);

    BddtHistoryItem itm = getItemAtPoint(pt.x, pt.y);
    if (itm != null) {
      popup.add(new GotoSourceAction(itm));
      popup.add(new GotoStackAction(itm));
    } else {
      GraphObject go = getObjectAtPoint(pt.x, pt.y);
      if (go != null && go.getValue() != null) {
        popup.add(new GotoValueAction(go));
      }
    }

    popup.add(getFloatBubbleAction());

    popup.show(draw_area, pt.x, pt.y);
  }
 GotoValueAction(GraphObject go) {
   super("Show this value");
   for_value = go.getValue();
 }