Javascript Amstockchart-多重比较不起作用；“数据集选择器”；是"；top"；

我正在使用amstockcharts。它运行良好，但当我将dataSetSelector的位置置于顶部时，它不允许比较多个图表。如果我出了什么问题，请告诉我

// DATA SET SELECTOR
var dataSetSelector = new AmCharts.DataSetSelector();
dataSetSelector.position = "top";
dataSetSelector.selectText = "select";
dataSetSelector.compareText = "compare to";
chart.dataSetSelector = dataSetSelector;