title: Highstock Series Compare to First Day of Boundary Instead of Previous Day
body: <p>I am working with the Highstock compare demo:</p>
  
  <p><a href="http://www.highcharts.com/stock/demo/compare" rel="nofollow">http://www.highcharts.com/stock/demo/compare</a></p>
  
  <p>jsFiddle:</p>
  
  <p><a href="http://jsfiddle.net/gh/get/jquery/1.9.1/highslide-software/highcharts.com/tree/master/samples/stock/demo/compare/" rel="nofollow">http://jsfiddle.net/gh/get/jquery/1.9.1/highslide-software/highcharts.com/tree/master/samples/stock/demo/compare/</a></p>
  
  <p>The associated code of the percent compare is as follows:</p>
  
  <pre><code>plotOptions: {
    series: {
      compare: 'percent'
    }
  },
  </code></pre>
  
  <p>If we set the rangeSelector to 1m (one month), and assuming today is August 15, 2016, then the first entry displayed is Tuesday, July 12. The values are MSFT: 53.21, AAPL: 97.42, and GOOG: 720.64. The Tooltip shows percentage changes of +1.18%, +0.45%, and +0.78%, respectively, over the previous day. But the problem is that the values for the previous day (7/11/2016) are not shown. This is confusing to the user, in my opinion. What I want to do instead is give each of these starting values a percentage change of 0%, so the left-side of the graph always starts at the origin. How do I do this?</p>
  
  <p><strong>UPDATE:</strong> I was thinking along the lines of something like this:</p>
  
  <pre><code>events: {
    load: function(e) {
      set_new_min_y_data_points(e);
    }
  }
  
  // ...
  
  function set_new_min_y_data_points(e) {
  
    for (var i = 0; i &lt; e.target.series.length; ++i) {
      // By setting the first data point to the same 
      // value as the second data point, we ensure 
      // that the series starts at the origin.
  
      e.target.series[i].processedYData[0] = e.target.series[i].processedYData[1];
    }
  }
  </code></pre>
  
  <p>...but this doesn't work. Even though the values of e.target.series[i].processedYData[0] are changed, the graph looks the same.</p>