Multi-Window Chat is a new feature for Microsoft Teams, which will enable you to multitask more efficiently by popping out your chat conversations into separate windows.
You will be able to engage in chat sessions in windows outside the Teams app.
There are several ways you can pop-out your conversations:
- Double-click on a conversation in the chat list.
- Click “Pop out chat” from the context menu for a chat in the chat list.
- Click the ‘pop out’ button in the top-right corner of the chat header.
- Use the slash command /pop name
- Double-click on an avatar picture
- Hover over a chat in the chat list and click on the ‘pop out’ button

Image courtesy of Microsoft
This new feature will start being rolled out in early April and will be completed worldwide by the end of May.