Progress Programming Handbook
Trigger Execution A trigger is executed only if all of the following are true: The widget is enabled for input. The trigger is currently active. The user performs the action associated with the trigger, or the application executes an APPLY statement that applies the trigger event to the widget. If the APPLY statement is not used, one of the following must also be true: Execution is blocked for input (for example, by a WAIT–FOR or UPDATE statement). The PROCESS EVENTS statement is executed.
A trigger is executed only if all of the following are true: