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 teamJamie commented
All, we keep hearing this is being worked on, but quarters have gone by with no update. Chats get lost, having a single pane means a lot of flipping between windows and the ability to only see one thing at a time. Needs updating.