NX How to Show and Hide Groupings in the Teamcenter Navigator

The 'Search', 'Browse Filter', 'Assembly Load Options', and 'Preview' groupings in the Teamcenter Navigator are missing. How can these groupings in the Navigator be shown again?

Please see the movie for details.

In the Teamcenter Navigator, have the user click the horizontal gray bar at the bottom of the Teamcenter Navigator.
Hold the cursor over the horizontal gray bar until the cursor looks like a double arrow, and then click the gray bar. Clicking on the gray bar will show/hide the groupings.