Hi, I've bought an used Game Boy Advance SP and when I tried to play an Game Boy/Game Boy Color game on it (Pokemon Red) I saw an darker area on top of the squared area of the image. It seems like some sort of shadow. My guess is that the cause of that might be the front light 'glass' that reflects the image. If i point a very strong light into it, it seems to disappear, and it is more noticiable in darker places. Can someone with a similar unit confirm that this 'issue' is normal? There follows two small pictures: Thanks in advance.