To save a draft just hit preview every so often. It's very helpful if you have a bad connection and you're writing a big post haha.
Hey, really a useful trick. I just checked. If I preview, I have a draft copy. Very nice. Definitely very much useful when forum faces DDOS attacks.
you need to go into a new message, and just under preview it says draft.
new message = new post. (Firstly, I misunderstood as new PM.)