Starfleet Jedi

There are times when I try to send a PM to someone, edit it after a preview, and the PM gets stuck in the outbox when I press "send". I figured that the outbox was some kind of "soon to be sent" placeholder, but even when I edit a message from the outbox which I thought I had sent, and then check (again) the "sent PMs", or sendbox in other places, I can't see it.
Thus I don't even know if the PM was sent at all... this thing confuses me a bit.