http://bugs.winehq.org/show_bug.cgi?id=28317
--- Comment #1 from paulo i30817@gmail.com 2011-09-08 11:39:37 CDT --- I forgot this happened with Planescape Torment too : it's a infinity engine bug.
It can be avoided with a virtual desktop of the same resolution as your desktop and setting the ingame resolution to that.