726: Mainline

Menu items can be menus. For example, the following uses the appendSubMenu: method to establish that the Options menu has a submenu, the Mode menu:

Menu new 
  title: '~Options';  
  owner: self; 
  appendItem: '~Food Type' selector: #resetListBox; 
  appendSubMenu: (Menu new 
                    title: '~Mode'; 
                    owner: self; 
                    ...)