zk.afterLoad('zkmax.inp, za11y', function() {
        var xChosenbox = {};
        zk.override(zkmax.inp.Chosenbox.prototype, xChosenbox, {
            _hliteOpt : function(target, highlight) {
                //original function
                var zcls = this.$s('option-hover');
                if (highlight) {
                    // clear old first
                    var oldHlite = jq(this.$n('pp')).find('.' + zcls)[0];
                    if (oldHlite)
                        jq(oldHlite).removeClass(zcls);
                    jq(target).addClass(zcls);
                } else {
                    jq(target).removeClass(zcls);
                }

                // za11y patch
                var inputNode = this.getInputNode();
                var activeDescendant = inputNode.getAttribute('aria-activedescendant');
                if(!target) {
                    inputNode.removeAttribute('aria-activedescendant');
                } else {
                    if(highlight) {
                        inputNode.setAttribute('aria-activedescendant', target.id);
                    } else if(activeDescendant == target.id) {
                        inputNode.removeAttribute('aria-activedescendant');
                    }
                }
            }
        });//zk.override
    });//zk.afterLoad