Comment 9 for bug 1501468

About an hour or two after resuming from suspend, pressing Control-N in Firefox caused this to reoccur. Trying the key combo again now is fine; opening 5 more windows without an Xorg crash. Not sure if it's a cause, as Xavier says, by number of windows, but my Firefox typically has 5 or more windows open, a video playing in VLC and a terminal.

I haven't see the issue occur with anything but Control-N so for me, my workaround is avoiding that key combo and we'll see if the issue comes up again when windows open.