title: HighStock: data series missing when zoom to larger range
body: <p>I am trying to draw multiple series in highstock, however one of the series will be disappear when I zoom out into larger range/period.  I can't figure out why ? Have a look at my code. Appreciate if you can tell me where I am making mistake and what is the solution.</p>
  
  <p>Using range selector : 
  "Extra1" info will be displayed on tooltips when mouse over when click on 1m, 3m, 6m and YTD. However, ‘1y’ and ‘All’ will showed that the Extra1 info is undefined or disappear.</p>
  
  <p>Using Scrollbar / Navigator:
  "Extra1" info will only appear if using navigator to zoom in a date range within 1 year or smaller period.</p>
  
  <p><a href="http://jsfiddle.net/ben5173/9orr32xd/" rel="nofollow" title="jsfiddle.net">jsfiddle</a> </p>
  
  <pre><code>    $(function() {
    var series1Data = [];
    for (var i = 0; i &lt; 1000; i++) {
      series1Data.push({
        x: (new Date()).getDate() + i * 100000000,
        y: Math.random() * 100,
        extra1: Math.random() * 100
      });
    }
  
    var series2Data = [];
    for (var i = 0; i &lt; 1001; i++) { //If you change this back to 1000 the series gets rendered
      series2Data.push({
        x: (new Date()).getDate() + i * 100000000,
        y: Math.random() * 100 + 100,
        extra1: Math.random() * 100
      });
    }
  
    $('#container').highcharts('StockChart', {
  
      chart: {},
  
      tooltip: {
        crosshairs: true,
        //shared: true,
        valueDecimals: 2,
        pointFormat: '&lt;span style="color:{series.color}"&gt;{series.name}&lt;/span&gt;: &lt;br/&gt;x:&lt;b&gt;{point.x}&lt;/b&gt; &lt;br/&gt;y:&lt;b&gt;{point.y}&lt;/b&gt; &lt;br/&gt;extra1:&lt;b&gt;{point.extra1}&lt;/b&gt; &lt;br/&gt;'
      },
  
      colors: ['#b30000', '#0000ff'],
  
      plotOptions: {
        series: {
          turboThreshold: 0 //larger threshold or set to 0 to disable
        }
      },
  
      series: [{
        name: 'Series 1 ;-)',
        data: series1Data
      }, {
        name: 'Series 2 :-(',
        data: series2Data
      }]
  
    });
  });
  </code></pre>