Comment 11 for bug 199960

Also, on the off chance that it is an xserver issue, I've packaged some xrandr bug fixes from upstream.

Please install the three X server debs from this url which have been patched with the fixes, re-test, and let me know if it improves things:

  http://people.ubuntu.com/~bryce/Testing/XrandrGui/

If not, can someone experiencing this bug please run gnome-settings-daemon in gdb and get a 'backtrace full'? The error messages provided don't give enough info to go on.