This feature request is still working its way through the backlog queue.
We are working on a better experience in Teams when a user is not connected to the internet. No timeline to share at this point, but we will keep you posted.
We’re currently working on defining a compact mode experience. I will post more details when we have more to share.
As we announced at Microsoft Ignite 2019 this morning, we are excited to confirm that Multi-window capabilities are coming to Microsoft Teams, and will start rolling out to the public ring early next year!
Alex & the Teams team