I know this is an old topic, but it apparently has not been resolved. We have been using Teams for about 6 months now and everything was going well. When I removed our SFB licenses, I learned that most of my users were still using SFB for Chat because they do not get a pop up or obvious notification of new chats in Teams.
Having the new Chat open in a separate window, when it arrives, would be ideal. But, in the meantime, just having a notification window similar to the incoming call window would accomplish what we need and let users know they have a new Chat.
Is this something that is currently being worked on?