Tooltips working when entering jqplot pie but not when moving from slice to slice (Firefox only affected)

问题

Tooltips work okay when entering piechart 'from outside' but the transition between slices causes the tooltip to disappear & the new one is not created.

Here is my jsfiddle snippet, closely based on helpful advice from this SO answer.

I know that how to get tooltips working for pie as a whole as have see another jsfiddle doing just that but I want the tooltip on top of the specific slice.

I have seen the bubble plots example on http://www.jqplot.com but since it uses plot1b.axes.xaxis etc I dont think it applies easily to pies or donuts?

 $(document).ready(function () {
var data = [
    ['Heavy Industry', 12],['Retail', 9], ['Light Industry', 14], 
    ['Out of home', 16],['Commuting', 7], ['Orientation', 9]
  ];
    plot2 = jQuery.jqplot('chart2', [ data ], {
        seriesDefaults: {
            shadow: false,
            renderer: jQuery.jqplot.PieRenderer,
            rendererOptions: {
                padding: 2,
                sliceMargin: 2,
                showDataLabels: true,

                highlightMouseOver: true
            },
            highlighter: {
                show: true,
                formatString: '%s',
                tooltipLocation: 'sw',
                useAxesFormatters: false
            }
        }
    });

    $('#chart2').bind('jqplotDataHighlight',                    
    function (ev, seriesIndex, pointIndex, data) {
        console.log("jqplotDataHighlight for " + data)
        var $this = $(this);
        $this.attr('title', data[0] + ": " + data[1]);
    });
    $("#chart2").bind('jqplotDataUnhighlight', function (ev, seriesIndex, pointIndex, data) {
        console.log("jqplotDataUnhighlight for " + data)
        var $this = $(this);
        $this.attr('title', "");
    });
});

来源：https://stackoverflow.com/questions/21918656/tooltips-working-when-entering-jqplot-pie-but-not-when-moving-from-slice-to-slic