title: HighStock Start Month rangeSelector And series.compare Not Working on Initial Load
body: <p>We are working on creating a stock chart showing several items even counts and their relative per cent change over time. The data is monthly and we have a range selector set up to allow for 6 months, 9 months, 1 year, and all data. On initial load we are selecting the 6 month range. We are noticing some strange effects. Here is a sample jsFiddle representing the issues:
  <a href="http://jsfiddle.net/wergeld/wq7eavq4/" rel="nofollow">http://jsfiddle.net/wergeld/wq7eavq4/</a></p>
  
  <p>The rangeSelector code:</p>
  
  <pre><code>rangeSelector: {
      inputEnabled: false,
      allButtonsEnabled: false,
      buttons: [{
          type: 'month',
          count: 6,
          text: '6 Months'
      }, {
          type: 'month',
          count: 9,
          text: '9 Months'
      }, {
          type: 'year',
          count: 1,
          text: 'Year'
      }, {
          type: 'all',
          text: 'All'
      }],
      buttonTheme: {
          width: 60
      },
      selected: 0
  },
  </code></pre>
  
  <p>1) On initial load the 0% "start" occurs in the October 2014 data points and the relative per cent change is calculated from this point. However, the first point shown in the chart is actually September 2014. This has some per cent change from (I am guessing) October 2014.</p>
  
  <p>2) When we change the selection to the 9 month range selector we see that the first point for June 2014 is the 0% value. Then if we click back to the 6 month range selector value you can see that now we have September 2014 as the 0% and the per cent differences for the later times are all different than on initial load.</p>
  
  <p>My questions are:</p>
  
  <p>a. Why are there 7 months shown when I set the count for that <code>rangeSelector</code> to 6 and why are there 10 months shown when I have it set to 9 months for the other range selector? Essentially for a given <code>rangeSelector.count</code> I am getting 1 more than I expect.</p>
  
  <p>b. Why is the 0% point different on initial load than it is when I click out of that range and back into that range?</p>