1. I dont remember but its a good idea working that way!
2. Configurable yeah it would be great!At first when a new message received it would have some kind of flash or popup or both or something like this.The time i dont know.Maybe until an answer,maybe stays forever as an osd.What do you think?If disappears after a short time it might be good some way to reopen it,if we want to send something and not open the classic wlm window.
3. Configurable too its a good step,like how many lines can be displayed.
4. It depends how the osd will be and how it displays the conversation etc.
5. Generally displaying.Should be an option for fullscreen if its possible and some kind of hotkey(configurable) to reopen or close immediately(if dont want to wait by the time it closes) in fullscreen when disappears.
I think i made it a little complicated