Mac Bookshelf: One Message When Toggling QuickShelf On and Off

SYMPTOMS

If you use Control Panel and disable QuickShelf, a message appears stating that you need to restart your Macintosh to make the change take effect. However, if you go back and enable QuickShelf again before restarting, you will not receive the message a second time. This message only appears the first time you toggle QuickShelf on or off during a particular work session.

If you ultimately do change the QuickShelf setting from what it was originally, you must restart your system for the change to take effect.