I have installed NoMachine Enterprise Workstation on my computer running Ubuntu 17.10 with the Gnome desktop and GDM, and even though I have a physical monitor connected to my computer any NoMachine client that connects doesn’t show the current X server, it only shows the option to create a new virtual server
Secondly, I have disabled GDM wayland in /etc/gdm3/custom.conf by uncommenting the line WaylandEnable=false, and I can confirm that the X server is running as I can connect into it though x11vnc.
Basically, I don’t want to use x11vnc, and would rather use NoMachine, but NoMachine won’t show the physical display