Update: I played with file permissions of this file (~/.config/xfce4/xfconf/xfce-perchannel-xml/displays.xml, added write permissions for all) and now at least I can change refresh rate. I still cannot change resolution, but it may be another bug as I can see display-config is actually trying to do something.
Update: I played with file permissions of this file (~/.config/ xfce4/xfconf/ xfce-perchannel -xml/displays. xml, added write permissions for all) and now at least I can change refresh rate. I still cannot change resolution, but it may be another bug as I can see display-config is actually trying to do something.