As Unity is based on users’ desktops Ubuntu, additions and hands emerging from the community to fill the gaps. Was clear that the classic menu of GNOME was one of those missing pieces to recover .
As explained in GNULinux.cat retrieve the classic menu in GNOME Unity is as simple as installing ClassicMenu-Indicator, an applet to the top panel along with the other indicators will make its function, as always, by category.
To install ClassicMenu
-Indicator must add the following repository PPP
Once installed you just have to restart session for changes to take effect and find this ClassicMenu-Indicator that many have missed. Or maybe not.