Rotating shift alt key doesn't work

On rotating tool guide tips

Tip: When you press and hold the Shift key to constrain the plane of rotation, you can press Alt (Microsoft Windows> or Command (OS X) to free the protractor from the inferenced plane. The angle of the protractor will remain the angle of the original plane, but now you can move the protractor to inference other geometry.

there doesn’t work “alt” keys on sketchup 2021 ver.