Settings / Colors & Fonts scrollbar issue

The "Settings" -> "Colors & Fonts" scrollbar started behaving differently about a week ago when I was using RubyMine build 856. I upgraded to build 873 today, but I'm experiencing the same issue.

Here is a video clip of the behavior in action:

http://www.vimeo.com/4320691

I'm on Windows XP SP3. If you need any more info let me know. It's not critical, it's just makes it quite difficult to scroll down the rest of the settings pages to change colors.

Thanks,
Steve