HighCharts:工具提示上可见的标签

Labels on my chart are showing over tooltip, which doesn't look very nice. I tried to play with zIndex, but to no result. How can I make tooltips not transparent? Here's my jsFiddle: http://www.jsfiddle.net/4scfH/3/

$(function() {
  var chart;
  $(document).ready(function() {
    chart = new Highcharts.Chart({
      chart: {
        renderTo: 'graf1',
        plotBackgroundColor: null,
        plotBorderWidth: null,
        plotShadow: false
      },

      title: {
        margin: 40,
        text: 'Podíl všech potřeb'
      },
      tooltip: {
        //pointFormat: '<b>{point.y} Kč [{point.percentage}%]</b>',
        percentageDecimals: 2,
        backgroundColor: "rgba(255,255,255,1)",
        formatter: function() {
          return this.point.name + '<br />' + '<b>' + Highcharts.numberFormat(this.y).replace(",", " ") + ' Kč [' + Highcharts.numberFormat(this.percentage, 2) + '%]</b>';
        }
      },
      plotOptions: {
        pie: {
          allowPointSelect: true,
          cursor: 'pointer',
          dataLabels: {
            enabled: true,
            color: '#000000',
            connectorWidth: 2,
            useHTML: true,
            formatter: function() {
              return '<span style="color:' + this.point.color + '"><b>' + this.point.name + '</b></span>';
            }
          }
        }
      },
      series: [{
        type: 'pie',
        name: 'Potřeba',
        data: [
          ['Firefox', 45.0],
          ['IE', 26.8], {
            name: 'Chrome',
            y: 12.8,
            sliced: true,
            selected: true
          },
          ['Safari', 8.5],
          ['Opera', 6.2],
          ['Others', 0.7]
        ]
      }]
    });
  });
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="http://code.highcharts.com/highcharts.js"></script>
<div id="graf1" style="width: 400px; height: 250px; float:left"></div>

推荐答案

你可以设置useHTML 并通过 css 定义自己的工具提示:

tooltip: {
    borderWidth: 0,
    backgroundColor: "rgba(255,255,255,0)",
    borderRadius: 0,
    shadow: false,
    useHTML: true,
    percentageDecimals: 2,
    formatter: function () {
        return '<div class="tooltip">' + this.point.name + '<br />' + '<b>' + Highcharts.numberFormat(this.y).replace(",", " ") + ' Kč [' + Highcharts.numberFormat(this.percentage, 2) + '%]</b></div>';
    }
},

.label {
    z-index: 1 !important;
}

.highcharts-tooltip span {
    background-color: white;
    border:1 px solid green;
    opacity: 1;
    z-index: 9999 !important;
}

.tooltip {
    padding: 5px;
}