http://bugs.winehq.org/show_bug.cgi?id=12051
--- Comment #17 from Tobias Jakobi liquid.acid@gmx.net 2008-08-20 14:56:03 --- Bug is still there with latest git master, but the appearance has changed.
It's now a single rectangular field with a gradient.
Also see: http://bugs.winehq.org/show_bug.cgi?id=14751
Bug #14751 seems to depend on ingame shadow settings, maybe there is a relation.