瀑布Highcharts上的Stacklabels

Question

我正在尝试将stacklabels添加到瀑布图表中。具有正“y”值的堆栈显示堆栈标签，但具有负“y”值的堆栈不可见。

http://jsfiddle.net/kGH8r/

$(function () {
$('#container').highcharts({
    chart: {
        type: 'waterfall'
    },

    title: {
        text: 'Highcharts Waterfall'
    },

    xAxis: {
        type: 'category'
    },

    yAxis: {
        title: {
            text: 'USD'
        },
        stackLabels: {
            enabled: true
        }
    },

    legend: {
        enabled: false
    },

    tooltip: {
        pointFormat: '<b>${point.y:,.2f}</b> USD'
    },

    series: [{
        upColor: Highcharts.getOptions().colors[2],
        color: Highcharts.getOptions().colors[3],
        data: [{
            name: 'Start',
            y: 120000
        }, {
            name: 'Product Revenue',
            y: 569000
        }, {
            name: 'Service Revenue',
            y: 231000
        }, {
            name: 'Positive Balance',
            isIntermediateSum: true,
            color: Highcharts.getOptions().colors[1]
        }, {
            name: 'Fixed Costs',
            y: -342000
        }, {
            name: 'Variable Costs',
            y: -233000
        }, {
            name: 'Balance',
            isSum: true,
            color: Highcharts.getOptions().colors[1]
        }],
        dataLabels: {
            enabled: true,
            formatter: function () {
                return Highcharts.numberFormat(this.y / 1000, 0, ',') + 'k';
            },
            style: {
                color: '#FFFFFF',
                fontWeight: 'bold',
                textShadow: '0px 0px 3px black'
            }
        },
        pointPadding: 0
    }]
});
});

我可以帮忙解决这个问题吗？