http://www.w3.org/TR/wai-aria/states_and_properties#aria-posinset http://www.w3.org/TR/wai-aria/states_and_properties#aria-setsize
BRB: Likely resolved. Need to investigate.
<rdar://problem/15710448>
This is not fixed, or at least it's not showing in AX Inspector.
I ran into this issue testing with VoiceOver. Looks like it also does not work with listitem/menuitem/tab/etc. I've only been able to see it work with the option role.