Actually, looking at the code, I don’t understand how the handler remains a LocalHandler after you called withHandler.
Truth be told, I wanted to raise that subject on the forum. I think that classes like EventEnablingPredicateFilter (but also EventSlopeFilter, etc.) should not have a withHandler method working like in AbstractDetector. Otherwise, the user can workaround the logic in LocalHandler, which means that it is either useless logic or it is a bug. Am I right?