extension.js

// GNOME extension w/ multiple icons
//
// tested w/ gnome-shell 3.8
// won't work w/ older versions of gnome-shell
//
const St = imports.gi.St;
const Main = imports.ui.main;
const PopupMenu = imports.ui.popupMenu;
const PanelMenu = imports.ui.panelMenu;

let button, button2;

function init() {
    button = new PanelMenu.Button(0.0);
    button._icon = new St.Icon({icon_name: 'system-run',
                                style_class: 'system-status-icon'});
    
    button.actor.add_actor(button._icon);
    button.menu.addMenuItem(new PopupMenu.PopupMenuItem("foo"));
    button.menu.addMenuItem(new PopupMenu.PopupMenuItem("bar"));

    button2 = new PanelMenu.Button(0.0);
    button2._icon = new St.Icon({icon_name: 'system-search',
                                 style_class: 'system-status-icon' });
    
    button2.actor.add_actor(button2._icon);
    button2.menu.addMenuItem(new PopupMenu.PopupMenuItem("hoge"));
    button2.menu.addMenuItem(new PopupMenu.PopupMenuItem("moge"));
}

function enable() {
    Main.panel._rightBox.insert_child_at_index(button.container, 0);
    Main.panel._rightBox.insert_child_at_index(button2.container, 1);
}

function disable() {
    Main.panel._rightBox.remove_child(button.container);
    Main.panel._rightBox.remove_child(button2.container);
}

Screenshot.png