Graphics issues on xfce on qubes r4.04

I have some graphic problems, non-vital minors that bore me enough, they are not the priority however I trust that someone can help me!

QUBES r4 installation, on a machine with nvidia desktop graphics card
During installation everything seems to be fine, standard xfc4 and standard drivers no changes.
Dual monitor configuration, inverted monitors ok, I open the display settings in dom0 and change the order I apply graphic glitches, all blocked and mirrored, the monitors have different resolution so a disaster! the only solution is to physically turn off the second monitor! I look for solutions I can’t find them I remove /home/user/.config/xfce4/xfconf/xfce-perchannel-xml/xfce-display-xml log off turning on the monitor log in everything back almost normal, monitor inverted as before but not mirroring, but the walpaper of qubeos default disappears, with it the menu in the right click! From here on I try to delete the files one by one until the entire folder is removed …/.config/xfc4… do nothing, I try to reinstall all the components xfc4 * xfdesktop xfwm4 xfconf, nothing to do, it obviously has to do with the user profile, at least I hope, but I don’t know where to put my hands … the fear is to do damage! lspci recognizes the graphics card even if not in all its components and clearly uses the nouvea!

Could anyone help me?