Ability to expand and collapse the whole tree on the documentation theme

We typically use the "Atlassian OnDemand Documentation Theme," which shows a tree of the space's pages in a Navigation Sidebar. It would be really useful if there was a button that allowed you to expand (or collapse) the entire tree.

Also, every time you go to a new page in the tree, the whole tree collapses. Please change it so that the directory remembers what was expanded even when new pages are loaded.