http://bugs.winehq.org/show_bug.cgi?id=33467
--- Comment #11 from Ken Thomases ken@codeweavers.com 2013-05-29 09:28:17 CDT --- I have submitted http://source.winehq.org/patches/data/96531 which fixes this in my testing. It makes it so that full-screen windows don't float when you switch to another app.