The way this screen works, it's very easy to change a setting just by touching anywhere on the screen.  After you've changed one, there's no easy way to know what the old setting was, or what the default is.  Plus, there are a lot of these settings (eight total) in this screen so they're easily confused.

The only way to get back to the defaults right now is to do a factory reset.  Please add a 'Reset shortcuts to default settings' option at the bottom of the menu.  A confirmation dialog after this is selected would also be good.