Game #120605 on tokyo but it also happened to me in other games.
Computer specs: Windows 7, Firefox 45.6.0
Two treasuries were in play. In clean-up I was asked to topdeck/discard in a dialogue. I accidentally deselected topdeck because I wanted to choose it (I thought clicking it would do that which is also a bit intuitive) and then the Treasury and buttons completely vanished. It was possible to get it back by using the arrow but it took me a bit to understand that. People on discord say it is a bug, so this is the report.
See screenshot.
Cheers,
Voltaire
I think this interface is poor. Looking at that picture, I can not definitively convince myself which option is selected. Same thing with Exchanging Travelers.