Black Background on Dashboard

Since upgrading to WP 3.3, the Dashboard shows a black background across the “above the fold” part of the page and in the footer but not inbetween. The same thing is true on the Comments page but all the other pages of the Dashboard look normal. Even stranger, I have three other WP installations on the same server that I upgraded at the same time and they all look normal.

I have tried reinstalling WP, both manually and from the upgrades page. I have tried deactivating/reactivating all the plugins. Can anyone suggest something I’ve missed?

Thanks.