Expanding means bringing into view any subentities associated with an
     entity.  Collapsing means taking those subentities away from view.
     A highlighted icon (a dark diamond) in front of an entity or subentity
     indicates that it has children and may be expanded or collapsed.  For
     example, when you expand the Node entity, its subentities, such as
     Event Dispatcher, Alias, etc. will appear.

1  –  how_to_expand_collapse

     There are two methods to perform the expand/collapse action.  The
     easiest way is to double-click the left-most mouse button on an entity in
     the main window.  (Of course, if you have changed your Session Manager
     Options and are using the Left-Handed Mouse Button Arrangement, use the
     right-most button instead.)

     Another way to expand or collapse an entity is to single click the
     left mouse button on the entity to select it and then select Expand or
     Collapse from the Actions pulldown menu.

2  –  how_to_see_ncl

     Some entities take longer to expand than others because the application
     is busy querying the system about the subentities.  For example,
     expanding routing circuit adjacencies will generally take longer on an
     intermediate system than it will on an end system.  If you are curious
     about what NCL commands the application is performing on your behalf,
     you can select Default Actions from the Options pulldown and enable
     NCL to display those commands.