http://bugs.winehq.org/show_bug.cgi?id=24113
--- Comment #1 from Andrew Nguyen arethusa26@gmail.com 2010-08-23 23:33:32 --- Works fine here in wine-1.3.1-68-g70d8fce, perhaps you should check that there's not a process still running for your wineserver and that it shuts down after you modify the virtual desktop setting.