http://bugs.winehq.org/show_bug.cgi?id=4432
--- Comment #15 from Wolfram Sang wolfram@the-dreams.de 2010-11-20 16:53:26 CST --- Actually, using a custom background only works if it is a 24 bit BMP, for 8 bit BMPs it is also broken. This gave me a hint resulting in the following patch:
http://www.winehq.org/pipermail/wine-patches/2010-November/096073.html
Let's see if it is the correct solution.