Just to add a few thoughts, this bug affects Google Chrome also.
The error is hard to reproduce, it happens anytime, even if in idle mode. However Chrome seems to do a lot of things in the background.
I've put this here just to ask if the bug could be somewhere else, like in the libxcb or libx11 that causes other applications to crash.
I upgraded a few days ago from 16.04 and there were no problems.
Just to add a few thoughts, this bug affects Google Chrome also.
The error is hard to reproduce, it happens anytime, even if in idle mode. However Chrome seems to do a lot of things in the background.
I've put this here just to ask if the bug could be somewhere else, like in the libxcb or libx11 that causes other applications to crash.
I upgraded a few days ago from 16.04 and there were no problems.