I am making a DOD Source map and when I added these attic windows they turned all black. It is possibly because I put a black texture behind the windows so you couldn't see through them? I don't feel like deleting them because they were kinda annoying to vertex manip. to the windows shape. Also I don't think they are worth creating a vis group. So do you think what I said is the problem? Here is a screenshot of what it looks like.
http://img142.imageshack.us/img142/6672/dodex6xu.png