highcharts - highstock 动画更新

Question

我正在寻找一种在更新时为 highstock 设置动画的方法。文档说动画的默认值为 true，但我在这个 highstock 示例中看不到任何动画：

chart : {
        events : {
            load : function() {

                // set up the updating of the chart each second
                var series = this.series[0];
                setInterval(function() {
                    var x = (new Date()).getTime(), // current time
                    y = Math.round(Math.random() * 100);
                    series.addPoint([x, y], true, true);
                }, 1000);
            }
        }
    },

完整代码：http: //jsfiddle.net/gh/get/jquery/1.9.1/highslide-software/highcharts.com/tree/master/samples/stock/demo/dynamic-update/