Clicking the 'new Identity' button in full screen on macOS causes the top and bottom of the browser to show white bars that do not go away

Full-screening TorBrowser then clicking the 'new Identity' button causes tor browser to come out of full screen and the top and bottom of the browser have large white bars.

Open TorBrowser 9.0a8 on macOS 10.15 and click the green full screen button.
Click the 'new Identity' button and choose to have a new Identity. Image attached showing the white bars.

Trac:
Username: Dbryrtfbcbhgf

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