Getting missing tags back on thumbnails

When I open PSE 11 in the Organizer and select all of my pictures I find them in the 'All media' & to the left of this I can see the sub folders that these pictures are in.

If I click the other 3 tabs across the top.'people','places','events' I get nothing at all.  All of these photos had tags on them.  In fact if I go down to the area where you create new tags I can find, names of places,people & events.  In other words this is a list of all of the tags that were previously created but never have been put back onto the thumbnails.

How do I fix this?