Any. If a website shows video through Windows Media Player, it does this. If I try to watch a DVD on PowerDVD, it does this.
I know how to fix it on PowerDVD, but the options I need to change are grayed out, and I can't figure out how to make them accessible.
..::EDIT::..
Good News: I was able to get into the option I thought I needed to adjust.
Bad News: It didn't do what it does in Quicktime when it does something similar.