you can always go in and amend/delete your posts for up to a couple of hours so it's easy to get rid of the 'extras' when you click again because nothing seems to have happened.
p.s. kim- how about greying out the button after it's been clicked?!
It's a bug and we haven't had a chance to sort it yet but if you delete a post with 'mark as edited' checked the post remains in the form you have seen. Unclick mar as edited first and the post disappears.