void installPopupMenu(String name, Program pgm) {
   Hashtable h = pgm.getMenus();
   if (h == null) return;
   String[] commands = (String[]) h.get(name);
   if (commands == null) return;
   PopupMenu popup = Menus.getPopupMenu();
   if (popup == null) return;
   popup.removeAll();
   for (int i = 0; i < commands.length; i++) {
     if (commands[i].equals("-")) popup.addSeparator();
     else {
       MenuItem mi = new MenuItem(commands[i]);
       mi.addActionListener(this);
       popup.add(mi);
     }
   }
 }