Ubuntu giving a Windows like ghosting effect with Firefox

I thought that this wouldn't happen in Ubuntu...

 

So I am using Ubuntu Feisty Fawn, and the latest version of Firefox 2. I was trying to refresh a youtube page so I can get sound working, and then firefox crashed. I was playing Neverputt at the time, and I moved the window around and this happened.

 

It only ever happens in Firefox. Why?

Done