Firefox 4 didn't get rid of the menubar. It put the menubar functionality in to a button on Windows, and provided the option of a button on Linux (the default is still a menubar). The menu button doesn't win us anything in Ubuntu, so we disable the button entirely and put the menu in the panel instead. Note that Firefox 4 and Chromium on the Mac also still have menubars.
Firefox 4 didn't get rid of the menubar. It put the menubar functionality in to a button on Windows, and provided the option of a button on Linux (the default is still a menubar). The menu button doesn't win us anything in Ubuntu, so we disable the button entirely and put the menu in the panel instead. Note that Firefox 4 and Chromium on the Mac also still have menubars.