Side Pop-open with sub-pages

This is an example of a website with extreme depth - but not that unusual for a site that has a lot of pages. 

Notice that when we are on this page or its sub-pages, the sub-page links appear.  If you go to the "Side Pop-open Links" page they don't. 

This in effect is demonstrating the drill down capability you can have on your website when you have the Pop-open links.