title: Highstock Change tick interval on range selector change
body: <p>I am unable to get the tickinterval to update in the following Jsfiddle: <a href="https://jsfiddle.net/rarwarrar/5xgoqjst/4/" rel="nofollow">https://jsfiddle.net/rarwarrar/5xgoqjst/4/</a></p>
  
  <p>Currently this:</p>
  
  <pre><code>   xAxis: {
      events: {
      setExtremes: function(e) {
        if (e.rangeSelectorButton.text === "2Hour") {
           $('#chart').highcharts().xAxis[0].tickInterval= 2700000 //45 min
           $('#chart').highcharts().redraw()
         }
      }
      }
     },
  </code></pre>
  
  <p>Is not working.</p>
  
  <p>For instance can the tick interval be set to every 45 minutes once '2hour' is clicked? </p>