Brace yourself for the vanishing menu bar because Mozilla has published an official feature list for Firefox 3.6
in the form of a guide for programmers who need to know about the changes.
The Firefox 3.6 developer guide
mentions an ability to automatically hide the menu bar
, a change that dovetails with sparer Firefox user interface designs
that Mozilla has begun exploring for Firefox versions 3.7 and 4.0. That's important for plug-in developers and others who use the menu bar to control their add-ons.