Bonfire "Done Selecting" moves after big hand, easy to auto-click

[ehunt]

This is game #87337003 on oregon. Turn ten I play a bunch of cards and then click Bonfire. I want to trash two coppers, but clicking twice on the copper file ends the buy phase and moves me to the wine-merchant-discarding part of cleanup, because the relevant button has moved directly over the coppers. My opponent let me undo and fix this; it happened again but there was a tiny part of the copper still clickable.