Reported by mdcurran on 2014-08-26 04:49
NVDA classes a frameset in a frameset as an NVDAObjects.IAccessible.MSHTML.Body, therefore the outer frameset is skipped when going parent, which means that asking if the innser frameset is in the outer frameset's TreeInterceptor results in false.
We currently use the Body class if this element's nodeName maps back to an NVDA role of document. Rather, we should first do the document check, but also then ensure that this element's uniqueNumber matches this element's document's body's uniqueNumber.
Possibly inner framesets should not get the document role, rather perhaps grouping, but this isn't that important to most users.

Quick HTML code that shows the bug:

<frameset rows="50%,50%">
<frameset cols="50%,50%">
<frame src="http://www.nvaccess.org"></fram>
<frame src="http://www.nvaccess.org"></fram>
</frameset>
<frame src="http://www.nvaccess.org"></fram>
</frameset>