My GTK setup has started to behave strangely - I belive since upgrading to FF 6 . The FF search bar, the Gimp menu and other similar controls are now decorated with a transparent white outline.

I do not have any customisations applied and I am unsure how to fix it. Any hints would be appreciated.

Update: Running OpenSUSE 11.4 64bit, GTK 2.22.1 , Gnome 2.32.1 .