dropdown_menu/static/src/main.js

openerp.dropdown_menu = function (instance, local) {
    "use strict";

    local.WelcomeWidget = instance.Widget.extend({
        start: function() {
            if (window) {
                window.alert('Hola desde un menu muito louco')
            }
        }
    })

    if (instance.web && instance.web.ListView) {
        instance.web.ListView.include({
            do_show: function() {
                this._super.apply(this, arguments);

                if (this.model != 'res.partner') return

                this.sidebar.add_items('print', [
                    {
                        label: 'Menu muito louco',
                        classname: 'oe_sidebar_print',
                        callback: function () {
                            var widget = new local.WelcomeWidget(this);
                            widget.start()
                        }
                    }
                ])
            }
        })
    }
}