A menu item's ID if the specified item exists. Otherwise, zero is returned.
Remarks
* The returned value doesn't change even if the application is restarted. * With this method, you cannot retrieve IDs of custom menu items (i.e. menu items created by API). To get custom menu IDs, please use the GetCustomMenuId method. * With this method, you can only retrieve IDs of menu items that don't have sub-menus.
