Ember js active class not working for nested or sub-routes

I have a link with route say about and couple of subroutes as about.college and about.campus.

Now I have about url in header top navigation bar and submenus in sidebar.

When I select any of menu from side bar the active class of about in main navigation bar is gets removed.

I want to make about link active when we are on about.campus or about.college route.

Any help would be appreciated.