Tried, but there is no xorg.conf on my system (what does not make any sense at all for me)… 
As a consequence, despite the commands issued I just loged out and in and there are no changes…
Tried, but there is no xorg.conf on my system (what does not make any sense at all for me)…
As a consequence, despite the commands issued I just loged out and in and there are no changes…