I performed an in-place upgrade from 12.04 to 12.10 by following the system update prompts. When I attempted to log in from an NX client (No Machine), my XFCE session was missing fonts almost everywhere, and some of the windowing elements were either missing or drawn incompletely. It was like this with XFCE and Unity, but less so with KDE.

The only way I could get the NX client to display all of the text and draw the GUI elements properly was to select the option Disable the render extension in the NX client options.

I tried reconfiguring the X server dpkg-reconfigure xorg, switching video drivers (from open to NVIDIA), switching window managers, disabling font aliasing. . . . Never got it to work again without disabling the render extension in the NX client.

Any idea what might have changed in the upgrade that would break my NX client settings?

Looking to see if this is related:

GTK unthemed and ugly over NX

Yes! Looks like the same problem:

nomachine NX: Text missing on all gtk interface (Unity and Gnome Classic)

Found a decent (so far) workaround that involves downgrading libcairo2:

http://ubuntuforums.org/showthread.php?t=2081746

I guess that will have to suffice until there is a libcairo fix.

BTW, disabling the render extension via NX client config wasn't working for me because the degradation in quality made illegible some of what text did appear.