title: Strange behavior of Highchart tool tip
body: <p>The tooltip in my Highchart is behaving strangely. It is living its own life. It doesn't show the tooltip of the point on which I hover, but shows the tooltip of any point randomly. </p>
  
  <p>Here is a JSFiddle example: <a href="http://jsfiddle.net/AeV7h/9/" rel="nofollow">http://jsfiddle.net/AeV7h/9/</a></p>
  
  <pre><code>$(function () {
  
  var data=[[28,0],[24,3],[16,10]];
  var param= { WodTag: "cur_spd", Name: "Current speed", Color: "#C6C6C6", LineStyle: "Solid", SeriesType: "line", LineWidth: 2, TickInterval: null,  MinValue: null, MaxValue: null, Decimals: 2 };
  
  $('#container').highcharts({
          chart: {
              height: 700,
              width: 400,
              plotBorderWidth: 1,
              plotBorderColor: '#E4E4E4',
          },
          xAxis: {
              title: {
                  useHTML: true,
                  text: param.Name + "( m/s  )",
              },
              gridLineWidth: 1,
              min: param.MinValue,
              max: param.MaxValue,
              gridLineDashStyle: 'Dot',
              tickInterval: param.TickInterval
          },
          yAxis: {
              title: {
                  text: 'Depth(m)',
              },
              reversed: true,
              tickLength: 50,
              gridLineDashStyle: 'Dot'
          },
          title: {
              text: null,
          },
          legend: {
              enabled: false
          },
          credits: {
              enabled: false
          },
          tooltip: {
              useHTML: true,
              formatter: function () {
                  return this.y;
              }
          },
          series: [{
              name: param.Name,
              data: data,
              color: param.Color,
              dashStyle: param.LineStyle,
              lineWidth: param.LineWidth,
              type: "line"
          }]
      });
  });
  </code></pre>
  
  <p>Can anyone help and tell me why it is behaving like this, and how I can fix it?</p>