SourceTree Mac 2.2 locks up after merging one branch into another

After upgrading to SourceTree 2.2, I now have a strange behavior.

After right-clicking on a branch and choosing "Merge

into

", the merge goes through, but the SourceTree UI then completely locks up. Clicking anywhere causes Mac OSX to beep as if the entire UI is locked/disabled. I cannot quit the app, or close any windows and the only way to recover is to Force Quit.

This happens consistently 100% of the time I use that feature. Attached is a video showing the behaviour. It's a bit hard to tell, but after I confirm the merge dialog, I'm clicking around anywhere in the UI and nothing is working anymore.