sclass PopupMenuMaker {
  settable bool allowScrolling = true; // ignored when using existingMenu
  settable MouseEvent event;
  settable PtInComponent ptInComponent; // if different from event
  settable IVF1<JPopupMenu> fillMenu;
  settable JPopupMenu existingMenu;
  settable bool addSeparator = true; // add separator if existing meun

  JPopupMenu menu;
  
  *() {}
  *(MouseEvent *event, IVF1<JPopupMenu> *fillMenu) {}

  public void run() swing {
    if (existingMenu != null) {
      fix();
      var menu = existingMenu;
      int emptyCount = menu.getComponentCount();
      if (addSeparator)
        menu.addSeparator();
      int emptyCount2 = menu.getComponentCount();
      fillMenu?.get(menu);
      if (menu.getComponentCount() == emptyCount2)
        truncateContainer(menu, emptyCount);
      //printVars("Extended popup menu", +emptyCount, +emptyCount2, n := menu.getComponentCount());
      packWindow(menu);
      //revalidate(menu);
    } else {
      new JPopupMenu menu;
      
      int emptyCount = menu.getComponentCount();
      fillMenu?.get(menu);
      if (menu.getComponentCount() == emptyCount)
        ret;
    
      if (allowScrolling) {
        menu = new JPopupMenu;
        JMenuScroller scroller = JMenuScroller.setScrollerFor(menu);
        scroller.fillMenu = toVF1(fillMenu);
      }
      
      ptInComponent if null = ptInComponentFromEvent(event);
    
      if (hasParentOfType JPopupMenu(ptInComponent.component)) {
        // component is in a menu itself. TODO: better positioning
        // Also this doesn't actually seem to work...
        menu.setInvoker(ptInComponent.component);
        menu.setVisible(true);
      } else
        menu.show(ptInComponent.component, ptInComponent.p.x, ptInComponent.p.y);
    }
  }
  
  svoid fix {
    JPopupMenu.setDefaultLightWeightPopupEnabled(false);
  }
}