This will stop all the NoMachine programs, included the !M icon. NoMachine will be restarted when you reboot the machine.
We are adding a dialog to let the user decide in just one click if he wants to start the server at the next boot. This change will be included in the next release, scheduled for tomorrow.
Note that the server configuration is being completely redesigned, to make it more comprehensible and easier to use. The fact users can’t disable the server in one click and have to disable the different “services” one by one (assuming users know what each “service” is) is a useful feature in a “enterprise” setting but clearly an annoyance for the rest of us.