Automatically all of a nav menu item's descendants as submenu items. Designed for pages but will work with any hierarchical post type or taxonomy …
When adding a page, category, or any hierarchical custom post type or taxonomy to your navigation menu (Appearance → Menus), this plugin allows you to optionally automatically add all descendants (children) of that menu item as submenu items.
In short, you’ll no longer have to manually maintain submenus when you add a new child page to your site.
Visit Plugins → Add New in your administration area and search for the name of this plugin.
_get_post_ancestors()
will/was deprecated in WordPress 3.5 and no longer works. Parts of this plugin have been rewritten to more properly get post ancestors.