Keyboard shortcut

[tutor10]

I had a keyboard shortcut for sharing and unsparing the screen.  It was the same shortcut for either sharing, or to stop sharing.  It stopped working so I set it back to the default, (where it says "stop/start screen sharing") but that only works for sharing the screen and not for stopping the share.  I tried setting a new shortcut but again it only works for sharing and not for unsharing.  I'd like to be able to stop the share with keyboard shortcut.  thoughts?