Right now in nsDocAccessible::GetState() we have a hack to determine if a document is focusable. We consider all HTML docs focusable and all XUL docs unfocusable. We need a better way. A XUL <iframe> could contain a scrollable XUL document, which should be focusable (we better make sure it is!) I was not able to find a way to use frame->IsFocusable() to find out if a doc is focusable.
Also, this is a follow-up from bug 375747. The new focusable check for nsDocAccessible comes from that fix.
Mass un-assigning bugs assigned to Aaron.
Editable frames should be focusable too, presumably.
fixed by bug 673958
Verified fixed and by inspecting the mochitests from bug 673958 in Mozilla/5.0 (Windows NT 6.1; WOW64; rv:10.0a1) Gecko/20110929 Firefox/10.0a1.