I think you should be able to see the fix here: https://code.launchpad.net/~andyrock/unity/fix-1308572/+merge/216216 https://code.launchpad.net/~andyrock/unity

I think you should be able to see the fix here: https://code.launchpad.net/~andyrock/unity/fix-1308572/+merge/216216 https://code.launchpad.net/~andyrock/unity/fix-1308572/+merg... I don't know exactly how the fix prevents the problem, though. As for "how this could happen".... it's code for a UI. There's always going to be weird timing issues, race conditions, etc etc. UI code is never as simple as it appears.