It was called the "location" bar ... bug report logged .
http://bugzilla.mozilla.org/show_bug.cgi?id=21344
Kevin Berridge wrote:
> I seem to remember one of the past versions of Netscape
> Communicator having a nice feature in it's mail system. Rather then
> having a whole a big list of Mail folders with a scroll bar it had a
> drop down list. It accomplished the same thing but it added a bit of
> "neatness" to the window. Prehaps we could add this functionality as
> another mail window option in the preferences? Just a thought,
> Thanks!
>
> Kevin
>
