Ubuntu’s Unity interface greatly resembles that of MacOSX, and that includes The Global menu, AKA The Mac Menu, which shows the Application menu(File, View, Edit, e.t.c.) in the top bar.
Macbuntu, an Ubuntu to MacOSX Transformation pack, which i was so tempted to try, didnt work too well for me, and thus I uninstalled it. Yet, it left the scars; in this case, by permanently messing up the global menu.
This is how i fixed it. (terminal):
sudo apt-get install appmenu-gtk appmenu-gtk3 appmenu-qt indicator-appmenu