http://bugs.winehq.org/show_bug.cgi?id=24579
--- Comment #45 from Vitaliy Margolen vitaliy-bugzilla@kievinfo.com 2012-01-03 08:01:58 CST --- The original problem was that _anytime_ one would move steam window(s) they would move twice as fast and might move completely outside the screen.
What you describing is a different issue of Wine loosing mouse up event when moving/resizing windows. I can reproduce that too. But it's a different bug.