1. The event is not triggered when you undo editing an existing record. 2. The event is triggered when you move to the new record. 3. The event is triggered when you undo editing a new record. 4. When your event routine cancels the undoing, the undo command is disabled. More details and sample document here: https://ask.libreoffice.org/t/how-is-the-macro-call-prior-to-reset-working/124092/6