code: protected void showPopupMenu(MouseEvent e) {
          if (onAboutToShow(e)) {
              JPopupMenu popupToShow = getPopupMenu(e);
              if (popupToShow == null) {
                  return;
              }
              popupToShow.show(e.getComponent(), e.getX(), e.getY());
              popupToShow.setVisible(true);
          }
      }
docs: Called to display the popup menu.