It's done now, you should be able to upgrade to 2.6 at https://www.dynarch.com/my/products.html.

To disable expand/collapse functionality just don't pass an items list at all.  Example:

new NavSection(parent_menu, "<a href='/contact/'>Contact us</a>");

Note that the third parameter is missing; if NavBar sees that it will disable expand/collapse functionality for that section and it can be used just as a plain link.