For the past little while ( maybe up to a week ), versions of E built from git are crashing when I right-click in a bryce to configure it. I've tried renaming my ~/.e and starting E - even with a fresh profile I still can't configure bryces - I get a crash every time.
Oh god... It's a thaw not imediately preceeded by a freeze?
But anyway I would rather just error out in this case. Don't thaw during post-event. In fact try to do as little as possible during post-event. Please try and not interact with the canvas during the post-event cb, just postpone everything to a job. I think that will solve most of your issues... I would prefer to keep the complexity around post-event cb as low as possible, even if that means many things don't work and just throw errors.