Comment 89 for bug 185311

The locking assertion failure sounds like bug 185311.

Since we're seeing a few issues with traces involving libxcb, I've prepared a non-xcb-enabled libx11 here: http://people.ubuntu.com/~bryce/Testing/libx11/ . (I'm not certain I reverted all the deps correctly, so let me know if there are dependency-related issues with this. You probably should save your old libx11 debs in case the lack of xcb causes problems in other apps.)

Would someone mind testing with this noxcb libx11 and see if it makes any difference?