Ok, with further testing, it looks like the original issue that I was trying to fix only affects Qt5 and newer, and the crash due to the fix only affects Qt4.

So for now, the simple work around is to only use the fix when the user is running Qt5+. I've just made a commit to do that. So hopefully that solves it for you.

Eventually I want to rework all the windowing backend (including sorting) so this kicks the can down the road a bit, but it will keep things moving for now.

Thanks for running/testing my dev branch. It's very much appreciated.