hi peek,
do you have any kind of other "shading" modes working ? like curvature analysis or multi color or random color ?
had a look just a few minutes ago because i was thinking shading and analysis could be mixed up in some cases but hmm, look weird. Did you assign some material to the surfaces you're trying to turn shading on ?
did you try with a basic scene with a single surface ?
tell me about it and i hope we can find a solution
cheers
CPU Core 2 Duo @2.2Ghz
Memory 4 GB DDR2
HDD 1 750 GB
Graphics Card GeForce 8500GT
Monitor Setup 1920x1080
OS Win 7 sp1