win 10 , Firefox 47 (64 bit) can not remember the last fold used by flash

In other environment(win 7 ,win 8 ) , when flash open a local file ,all  the browser will remember the last fold used by flash .

In win 10, edge and chrome also does, but Firefox can't .Every time when FileReference.browse() , Firefox will open the default fold of documents.

I think this is a bug of Firefox.

hope flash stuff can also report this bug to Firefox's stuff.

thanks