Hi TammyKielty-2658,
Do you meant that you want to popup the calendar window?
If so, as Luca said, only chat window can popup. When you are in a Teams meeting, the meeting window is also popped up.
If it cannot meet your requirements, we recommend you that please give a feedback to https://microsoftteams.uservoice.com/forums/555103-public/suggestions/37941184-looking-for-the-ability-to-dock-teams-to-the-side. Microsoft will always focus on customer’s feedback and experience. Some new features would be added to the services based on customers' feedback in the future, and your good ideas will be very helpful for them to improve the service.
Your time, understanding and cooperation will be highly appreciated.