Just to confirm...Yes, the custom iProperty with Yes/No (Boolean) type value works OK too, as long as the rule is under the 'iProperty Change' event in the Event Triggers dialog on the This Document tab of that part. I just tried it on one of my sheet metal parts. The rule gets the FlatPattern object, then checks the value of that custom iProperty. If it is True then enter into edit mode of the FlatPattern ; if False, exit edit mode. We can drop that custom iProperty into a simple iLogic Form, and it will look like a drop-down list, with only those two values (Yes / No). Each time I change its value, the edit mode changes.
Wesley Crihfield

(Not an Autodesk Employee)