I was about to update AppCode on my Mac (under Sierra 10.12.1). I launched Jetbrains Toolbox app, and got the pizza-wheel-of-death (on the whole screen when just launched, then just on the icon when clicked somewhere else). Of course there was nothing to do (impossible to click on icon). I could just quit the app through Activity monitor (where it was shown as non responding). I found nothing explanatory in the Console, and reinstalling the app did nothing better.
When trying to report this problem, I could not find a dedicated place for this app - sorry about that - but I think this app deserves it.
I hope this report helps. Do not hesitate to contact me if you want further details.
I love JetBrains apps - that is why I want them to work !
Best regards and thank you very much,
-- EDIT --
Found the bug tracker and created an issue : Toolbox shows pizza-wheel-of-death when launched