dropdown menus

I am urgently looking for a hierarchical multi level multi select dropdown menu similar to the Drop Button 2 at http://www.bosin.net/ng/index.html or does someone know whether we can implement this menu on Drupal ?

I have created a intranet using Open Atrium 2 and having some problems with the menu structure. So far I have created 1 space with 6 sections under it. While creating documents under the section the menu option does not allow me to use the section pages as the parent. I only see the Group Menu. I would like to have a section menu that is expandible with child pages. Am I missing something in the structure.