N360 quarantined xul.dll (Firefox 36.0a1)

On 10/22/2014 Firefox (Nightly) was performing a daily update. I have been using this version of Firefox for months.

During the update I received error messages from N360.

Then Firefox displayed this error message on start-up.

So I opened Security History and found:

Xul.dll proved to be a Firefox file.

This hasn't happened before or since.  I notified Mozilla. I got no response to see if that particular build of xul.dll was infected.

I can't find a place on Norton to report this.

When I followed the More Info link it took me to Norton Enterprise.

TIA for any suggestions.