https://bugs.winehq.org/show_bug.cgi?id=8365
--- Comment #31 from Goblinstomper@gmail.com --- (In reply to Erich Hoover from comment #30)
(In reply to Goblinstomper from comment #29)
... So, I guess it is possible that the prolonged alt-tab at step 4 fulfilled the same 'alt stuck' behavior you encountered?
Could be, it also could be that (for some reason) the issue is not present when you are in fullscreen mode or that the keypress you tested was not sensitive to having the Alt key pressed. I suspect that when the Alt key is "stuck" that there are some operations that behave in unexpected ways.
I repeated your way of testing (or at least I think I did). I did not see an option to run the game in windowed mode, so I assumed that meant that you had run the game in a virtual desktop as per the winecfg setting. Doing this I was able to reproduce the 'backspace does not work' part (including 'hold down alt for a while and it'll work again), but apart from backspace the multiplayer name field accepted all characters/key-presses. Running the game in full-screen backspace is functional even after tabbing out and in and at no point does 'alt' seem to be 'stuck'.