Consider banning aria-hidden on some elements

[aleventhal]

Consider disallowing aria-hidden content on certain elements, such as:
body, html elements (if you need to hide an iframe, you can still put it on the iframe element).

This is one of the places where aria-hidden gets misused, probably because authors may naturally assume that they can put aria-hidden=false on a descendant to unhide it, which does not work.

For example, well-meaning authors trying to keep users inside a role="dialog" and want to hide the rest of the page, may put aria-hidden=true on the body, and aria-hidden=false on the dialog.

[aleventhal]

Duplicate of issue #1254

[pkra]

I think this can be closed as a duplicate.