an example can be found on AMOSPro_Tutorial:Tutorials/Menus/Menus_1.AMOS
If you use CHOICE on it's own, it returns a value of True (-1) if the user has selected a menu item, or false if the menu hasn't been accessed.
There's also a second version which allows you to read the actual item which has been chosen.
test holds the number of the item which has been highlighted by the user. level is the "dimension" of the menu to be tested.
Level 1 = the title line
Levels 2 through 8 read a submenu at the appropriate level.