I have managed to find a bug of some sort which I believe is related to Wine, but the manifestation of this bug is that while alt-tabbing, if you hold alt-tab and click on a different app in the graphical-popover, Ubuntu stops responding to any input and no longer allows me to control the gui.
Ctrl-Alt-F1 to lock the device allows me to log back into the exact same broken state. I can use a different TTY to examine processes, but killing the app processes for the apps I'm using doesn't solve the issue.
Surely there must be some way of poking Ubuntu in order to regain control of the gui, but I don't know where to start. Some process I can kill? A signal I can send?
Currently my only solution is to reboot, and I'd like something more robust while I track the problem down.
A bonus would be if someone knows what this specific problem is and can help me solve it, but for right now I'd settle for regaining control of my machine.