The Popout option in the Chat App allows you to view chat conversation without website content in a separate browser tab.
You may open Chat App in a new tab by clicking on the Popout icon as shown below:
Upon clicking, the chat application will be opened in a new tab as standalone app. It will occupy the full screen as shown below:
This full screen mode of the Chat App has chat list on the left side. The main area shows one thread at a time.