on-demand in menu-item-container<%>

Called when the user clicks on the container as a menu bar (before the user sees any menu items), just before the container as a popup menu is popped up, or just before inspecting the menu bar containing the item for a shortcut key binding.

If the container is not a menu bar or a popup menu, this method is normally called via the on-demand method of the container's owning menu bar or popup menu, because the default implementation of the method chains to the on-demand method of its items. However, the method can be overridden in a container such that it does not call the on-demand method of its items.

• (send a-menu-item-container on-demand) -> void

  Calls the demand-callback procedure that was provided when the object was created, then calls the on-demand method of the contained items.