Bug 86964, "MSDN page displays with one frame overlapping and obscuring
another," was recently marked as "Fixed" and "Verified". According to the
Bugzilla comments:
When I first opened the given URL the top frame top.asp is
not completely visible. But if you drag the bottom frame its
completly[sic]
visible.
I would not consider that "Fixed". One should not have to drag frames
around in order to get a page displayed correctly. Since there is a simple
workaround, I can see lowering the bug's severity to "minor". But I am
surprised that Mozilla QA would consider this "Fixed".