Video playback strangeness

[Grant]

When I'm playing a video fullscreen that has something moving in a
window behind it (like a progress bar), the video will flash right
over the spot where there is movement behind it.  I stripped my
xorg.conf down a while ago and I'm wondering if I should add something
back in to fix this.  The only modules I'm loading are glx, dbe, and
extmod.  I'm using the nvidia drivers.  Does anyone know what I'm
talking about?

- Grant