I’ve got also a problem with RHEL7 and virtual desktop. I’ve installed NoMachine Workstation 4.2.27-2 version on RHEL7 server and NoMachine 4.2.27-2 client version on CentOS 6.2.
I be able to connect to the physical display but i’ve got an error when i try to use a virtual desktop : “Oh no! Something has gone wrong”
And i’ve got only “Logout” button.
Did you have this error?