MenuChoice
MenuChoice See if user attempted to select a disabled item returns high word is menu ID, low word is item number
(i.e., no selection made). It identifies the menu and item at which the mouse
was pointing when the button was released (even if the item is disabled).
Returns: a 32-bit long that indicates which menu and item was pointed to by the mouse. It is made up of two values as follows:
High Word menu ID of disabled " selection
Low Word item number of " selection". If 0, then the mouse
was over the menu title or outside the menu.
Notes: This can be used to see if the user has chosen a disabled item from a menu
at which point you could display a help message.
MenuChoice works by returning the current value in MenuDisable (and on older Mac systems, you can read this variable to obtain the item
number). If you create a Custom Menus, this function will return garbage unless your custom code puts the information into that variable.