sclass listPopupMenu_Maker {

  new L menuMakers;

}

static Map<JList, listPopupMenu_Maker> listPopupMenu_map = new WeakHashMap;

static new ThreadLocal<MouseEvent> listPopupMenu_mouseEvent;

static new ThreadLocal<Bool> listPopupMenu_first;

// menuMaker = voidfunc(JPopupMenu, S item)

static void listPopupMenu(final JList list, fO menuMaker) {

  final bool first = isTrue(getAndClearThreadLocal(listPopupMenu_first));

  awtIfNecessary {

    listPopupMenu_Maker maker = listPopupMenu_map.get(list);

    if (maker == null) {

      listPopupMenu_map.put(list, maker = new listPopupMenu_Maker);

      final listPopupMenu_Maker _maker = maker;

      list.addMouseListener(new MouseAdapter {

        public void mousePressed(MouseEvent e) { displayMenu(e); }

        public void mouseReleased(MouseEvent e) { displayMenu(e); }

        void displayMenu(MouseEvent e) {

          if (e.isPopupTrigger()) {

            new JPopupMenu menu;

            int idx = list.locationToIndex(e.getPoint());

            O item = list.getModel().getElementAt(idx);

            list.setSelectedIndex(idx);

            int emptyCount = menu.getComponentCount();

            listPopupMenu_mouseEvent.set(e);

            for (O menuMaker : _maker.menuMakers)

              pcallF(menuMaker, menu, item);

            // show menu if any items in it

            if (menu.getComponentCount() == emptyCount) ret;

            vmBus_send('showingPopupMenu, list, menu);

            menu.show(e.getComponent(), e.getX(), e.getY());

          }

        }

      });

    }

    if (first)

      maker.menuMakers.add(0, menuMaker);

    else

      maker.menuMakers.add(menuMaker);

  }

}