Selectmenu: Use button element instead of anchor, makes click-on-label work. Add aria-live to announce changes in JAWS/Firefox while menu is closed. Remove aria-labelledby as the label element is now the label. Still terrible in IE9/JAWS, way better with Safari/VoiceOver.
Selectmenu: Remove aria-expanded updates, not being useful at all. Remove labelledby on menu to avoid double announcement. Remove aria-activedescdent updates on button, as that breaks in IE.