Did you install any monitor-specific drivers?
Are you experiencing any problems with 3D-accelerated software?
StockSubmitter uses WPF (Windows Presentation Foundation), it is DirectX-based hardware accelerated interface framework, so basicly if there are any problem with drivers/acceleration/DirectX, it can cause such issues.
Ok, thanks, WPF has to be the cause of the interface issues. So it's video-card related. I have an ATI Radeon 6870, by the way. I also have the latest Dell drivers for my monitor and am not experiencing problems with DirectX (11) or 3d-accelerated software...
Edit: Tweaking the settings in the CCC (ATI's Catalyst Control Center) seems to have fixed it. No more black-outs. Probably had something to do with AA-settings not being set to "Use application settings", but I can't really figure out which setting caused it.