I think I'm certain. It has been a while since I have played with DirectDraw7, so I've forgotten some of the details. I know from my code that I only added a clipper if it was not in fullscreen mode. I might have to give it another test over the weekend.

Just spent a few minutes looking over my old code. It seems that I always clipped the rects myself before using BltFast. The clipper was just to handle overlapping windows.

10:20pm on a Friday night and I'm still at work. One week to go till the next milestone and four levels to complete. Such is the life of a games developer...