Comment 9 for bug 279770

Tom,
That is that latest version of human-theme. I suppose problems could exist if your current install is carried over from development. Have you tried re-installing the human-theme package? If not, let's try, but please don't remove from apt-get as ubuntu-desktop depends on human-theme.
   sudo dpkg --force-depends --purge human-theme
   sudo apt-get install human-theme
You may need to restart your X session to see if the change takes effect. Does it seem better?