In my case (see comment #4 above) it turned out that the lack of menu was caused by unnecessary presence of indicator-applet-appmenu in my GNOME panel. After removing the applet from panel, the menu was back.
In my case (see comment #4 above) it turned out that the lack of menu was caused by unnecessary presence of indicator- applet- appmenu in my GNOME panel. After removing the applet from panel, the menu was back.