I'm encountering issue explained in this topic:
The only solution which was mentioned there was attaching second monitor before turning on the laptop. This solution works for me but the problem is that I would like to have my second monitor above the first one - now after linux starts it is located to the right from the first one. When I try to change it through "Display" GUI linux freezes.
I had an idea to change this setting manually in ~/.config/monitors.xml file but it occurs that i cannot read it - cat shows nothing, vim shows only random characters string. Why this file cannot be read?
Also if you have other ideas how to change default position of second monitor (as stated before I cannot change it after system start up) I would be very grateful.