Exiting full screen mode forces window to lock size

If a Minecraft client has entered fullscreen mode then leaves it, it will be stuck in the default size for the window, and isn't adjustable.

Note: I found https://bugs.mojang.com/browse/MC-77912?jql=text%20~%20%22window%20mode%22 but it was marked as resolved with no comment, and it isn't actually fixed.