SYSTEM.TRIGGER_MENUOPTION
SYSTEM.TRIGGER_MENUOPTION is provided for backward compatibility with existing applications. It replaces the Menu parameter :SO and provides exactly the same behavior as the :SO Built-in substitution parameter.
The value of the :SO Built-in substitution parameter is predefined and always initialized by Forms at runtime. The value of the Built-in parameter :SO is the current menu item (Selected Option).
:SO returns a string value with the format <menu_name>-<index number> where index number is the number of the item in the menu, for example:
FILE_MENU-1
EDIT_MENU-3
Note that the index number is based on all the items in the menu, not just those that are displayed.