https://bugs.winehq.org/show_bug.cgi?id=49933
--- Comment #56 from Rafał Mużyło galtgendo@o2.pl --- (In reply to Rémi Bernon from comment #55)
Given that all WM seem to suffer from it, it's maybe even an X server bug.
Actually, that pretty much hints towards a difference in Windows/wm-spec implementation.
Also, while I do not recall particular titles, I do recall that on several occasions when a fullscreen game has crashed, its crash dialog also appeared below its window and couldn't be raised.