scrolling problem in firefox

Created an attachment (id=3412)
Firefox scrolling smear.

I'm running bootcd-38690-dbg.7z. When I run firefox downloaded using the
downloader, I upgraded without formatting from 0.3.7, I notice a scrolling
problem. Go to http://www.reactos.org/ and try to scroll up and down
and you will notice that ads on the left side of the screen smear. I
have an attached screenshot of the problem.