http://bugs.winehq.org/show_bug.cgi?id=27779
--- Comment #73 from Andre andre_lacerda25@hotmail.com 2011-09-15 22:36:50 CDT --- A also have this problem while trying to play Mass Effect 1 on Steam. It seens to me that the bug happens only with particulary games. I tried Alien Swarm from steam too and for my suprise no bug.
The bug also happens only when "Emulate a virtual desktop" is checked and checkbox "Automatically capture the mouse in full-screen windows". Unfortunately dual monitors users have to emulate the virtual desktop and then capture the mouse for being able to play.