Right now it's possible for a web page to make an element aria-hidden even if it's focusable.

If it ends up getting focus, accessibility events fire on an ancestor of that element, so there's no way for a screen reader to identify the element that's focused.

I propose that if an element is *focusable* but not actually focused, we continue to hide it from the accessibility tree. But if an element actually takes focus, we override aria-hidden and make the element part of the accessibility tree.