As far as I’m aware, clipboard sharing can only be disabled from the computer that is being controlled, in Server’s security settings.
Let’s say we have a case like this:
I’m controlling a remote computer which could potentially be compromised. If it’s compromised it could reenable clipboard sharing, so anything I copy on the machine from which I’m controlling the remote desktop could start getting captured.
I think it would be better security-wise to allow disabling clipboard sharing from both the client and the server.
For example, if I use a VirtualBox VM, I control clipboard sharing from the host, so even if the VM gets compromised, the host clipboard could never get accessed. But this doesn’t seem to be the case for NoMachine currently.