How do I exit full screen mode with Lightroom Classic, please?

[Terrycanon]

Can anyone help, please? Lightroom Classic has suddenly started filling the whole of the screen on my Mac, and I am unable to reduce its size. I like to use the little arrows in the corners to reduce or increase the size of Lightroom Classic and Photoshop - I don't want it filling the whole screen. Now the little arrows have no effect. Can't find any solution online. In the menu Window at the top of the portal there is a command for "Fill screen," but none telling how to exit it. The little arrows are working normally to reduce the size of Photoshop on my screen. It's just Lightroom Classic. Any ideas would be greatly appreciate.

 

[Terrycanon]

Phew! I've now sorted it. Shift and F. I tried everything else then stumbled on the answer. I hope this might help somebody else sometime. Cheers.