This is a new one,... and a strange one at that. Especially because the pane on the left works just fine.
Did you game work in the past? If yes, also this version or just an earlier version?
Did you try any custom modifications to your own game?
Did you run the game with the -columnconvert or -lightconvert options? (Don't! If you haven't, don't try this!)
What happens when you possess a creature?
Do you have any troubles with playing other games?
I have no proper solution for you so far,... you could try playing in windowed mode, changing the resolution of your game, or force your video driver (use the launcher, run options, check 'force driver' and try both directx and windib).
If all else fails, you could also try to reinstall the game.