Not sure if this has been suggested but would be a good feature.
I would like to see when someone sends a message you still get a red bubble, upon clicking the button where the bubble is, it opens the "pop-out chat window".
I feel this will reduce the amount of database calls with loading the member list showing how many online and chatting, not that it's much of a problem but would increase page load speed and also keep things nice tidy and simple.
Just an idea! :D