Hmm, when using tabbed conversations for Stuffplug ng (the latest one, the one that is compatible with msn 6.2 only...) I closed all of the tabbed conversations one-by-one by going
File > Close Conversations. I closed the final conversation, and was left with a blank window, that had the name of the person I was speaking to on top and the stuffplug logo.
So then I started messing about (dodgy, I know), and changed the size of the window, then, I got bored and closed the window. Somebody just spoke to me, and this happened: