I got the same problem. And to make the workaround work, I had to UBUNTU_MENUPROXY instead of UBUNTU_MENU_PROXY.
$ UBUNTU_MENUPROXY= emacs -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/673302 Title: appmenu-gtk breaks dynamically created Emacs Gtk+ menus -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
