Recommended WAI-ARIA implementation for navigation bar/menu

Question

We are in the process of implementing (i.e. adding) WAI-ARIA support to the main navigation menu of a web portal. Menu is the one shown here:

Answer 1

The ARIA design patterns provide expected UI behaviour for a range of custom controls http://www.w3.org/TR/wai-aria-practices/#aria_ex use of esc key to close and return to triggering element upon close is standard UI across desktop and web. Try it on any Google docs app (for example).