Apparently you are looking at a problem derived of the Vista core, and how the dirvers and specially the mission editor works in that environment
Suggestions:
-Set the program in compatibility to WinXP (If that exists in Vista, dunno cause I'm still on XP)
-Try newest drivers for graphic card, and also different desktop resolutions/colour depth.
-As last resort, use Virtual PC enviroment to work in an XP environment.