Hi @HARUTO_WIZARD
Based on our testing, we are able to reproduce your issue in the Teams web client, as this is by design of the web client.
You need to uncheck it by clicking the check mark to the right of "Full Screen", then click "Full Screen" again to enter full screen mode.
We apologize if this feature has caused any trouble to you. You can send a feedback directly to Microsoft Feedback to add it in future updates.
Many features of our current products are designed and upgraded based on customers’ feedback. With requirements like this increase, the problem may well be released in the future.
Thanks for your understanding and support.
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