I am afraid I had problems to produce backtrack:
1. apport says "No pending crash reports. ".
2. command sudo gdb /usr/bin/Xorg /etc/X11/core results with /etc/X11/core: No such file or directory.
For other methods from https://wiki.ubuntu.com/X/Backtracing I am probably a bit too lazy. Sorry.
I am afraid I had problems to produce backtrack:
1. apport says "No pending crash reports. ".
2. command
sudo gdb /usr/bin/Xorg /etc/X11/core
results with
/etc/X11/core: No such file or directory.
For other methods from https:/ /wiki.ubuntu. com/X/Backtraci ng I am probably a bit too lazy. Sorry.