static JMenu addToMenu(Component c, S menuName, O... items) {
  ret addToMenu(getFrame(c), menuName, items);
}

static JMenu addToMenu(final JFrame frame, fS menuName, fO... items) {
  ret (JMenu) swing(func {
    JMenuBar bar = addMenuBar(frame);
    JMenu menu = getMenuNamed(bar, menuName);
    bool isNew = menu == null;
    if (isNew)
      menu = new JMenu(menuName);
    fillJMenu(menu, items);
    if (isNew) {
      bar.add(menu);
      revalidateFrame(frame);
    }
    ret menu;
  });
}