AddSelectBox in Qooxdoo

/** A listItem which support button on the right side */
qx.Class.define("c.component.AddSelectBox",{
    extend : qx.ui.form.SelectBox,

    events:{
        /** When user click on add button */
        "add" : "qx.event.type.Event"
    },

    /**
     * Constructor
    */
    construct:function(){
        this.base(arguments);

        var addButton = new qx.ui.basic.Image("c/icons/add.png");
        addButton.addListener("click", function(){
            this.fireEvent("add");
        }, this);
        this._add(addButton);
    }
});