Screen corruption under Xen DOM0 in firefox

[David Brownlee <abs%absd.org@localhost>]

        I'm trying Xen on my NetBSD 5.0 laptop and one thing I've
        moticed is that the Firefox window seems to suffer corruption
        when focus is gained/lost (this is under gnome on a Thinkpad
        T60p using the radeonhd driver on a ATI MOBILITY FireGL V5250

        An example is at:
        http://mono.org/abs/xen-x11-corruption.png

        Note that the 'Tools' on the menu bar has been garbled, as has
        part of the webpage.

        Has anyone else seem anything similar?