zk.afterLoad('zul.wgt', function () {
    // zk.wpd:20167 Uncaught TypeError: Cannot read property 'floatZIndex' of undefined
    var _xNotification = {};
    zk.override(zul.wgt.Notification.prototype, _xNotification, {
        reposition: function () {
            this.$supers('reposition', arguments);
            if (this._ref) this._fixarrow(this._ref);
        },
        // Zajisteni spravneho z-indexu (ZK dava vzdy 1800+)
        _maxZIndex: function (ref) {

            var parent = ref.parent,
                    refn = ref.$n(),
                    pzi = 1;
            if (parent) {
                pzi = this._maxZIndex(parent);
            }
            var zi = (refn && refn.style && refn.style.zIndex) ? zk.parseInt(refn.style.zIndex) : 0;
            return (pzi && pzi > zi) ? pzi : zi;
        },
        _fixarrow: function (ref) {
            _xNotification._fixarrow.apply(this, arguments); //call the original method
            //do whatever you want

            var zi = this._maxZIndex(ref);

            this.setZIndex(zi ? zi + 1 : 1, {fire: false, floatZIndex: true});
        }
    });
});