Switch back to X in newest Ubuntu instead of using Wayland

Some applications like upWork client won't make screenshots in Wayland, so switching back to X is a solution in newest versions of Ubuntu.

To do that edit the gdm configuration file:

sudo vim /etc/gdm3/custom.conf

And make these lines to be:

[daemon]
# Uncomment the line below to force the login screen to use Xorg
WaylandEnable=false

Reboot and enjoy