It tends to happen on different entities. This one in particular is an .hmp file with black areas on it. Overlay doesn't get rid of them, however transparent and alpha = 100 does--but I need to find another way because this interferes with display of some sprites over the .hmp.

I've also had instances of sprites with black areas that don't completely disappear with overlay--but instead leave black parts and artifacts and look crummy. I usually clear this up by combining overlay with flare. As I understand setting the overlay flag by itself should be sufficient to clear these problems up, shouldn't it? Thank you.