@Override
      public void actionPerformed(ActionEvent e) {
        // if popup is not visible, make it visible
        // if popup has not the focus, pass it the focus
        // else: move to the first visible element in the choices
        if (popup.isVisible()) {
          if (popup.isPopupFocused()) {
            popup.selectDown(true);
          }
          else {
            popup.setPopupFocused(true);
          }
        }
        else {
          showChoices();
        }
      }
@Override
      public void actionPerformed(ActionEvent e)