I'd advise to put communication with NRS in seperate, non-GUI threads. That's what I do in my client, except for things like sending NXT which I don't want to go through the more complex logic of another thread.
NRS is servlet inside Jetty, so it is multithreaded by design. The only thing developer must take care - not to syncronize too much on global objects, but seems like Jean-Luc know it well.