The launcher is automatically closed once gammaray attaches itself to a process, the client is then started. However as far as I'm aware there is no way to go back from the client to the launcher. Moreover when you close the process without deattaching it first, the Connection lost dialog is shown, which upon clicking "OK" simply closes the client window.
It'd be better to add a button to this dialog which would allow user to return back to the launcher, instead of having to reopen the launcher manually each time this happens.
Such feature would be useful when debugging, as the Qt process is usually started inside an IDE and then terminated by it too, which causes me to click "OK" in the connection lost dialog and manually reopening the launcher each time.