title: Why HighChart hangs browser?
body: <p>The problem is that I have code like that:</p>
  
  <pre><code>$(function(){
      data = [
               [1315522800001, 9],
               [1317596400000, 3],
             ];
      // Create the chart
      window.chart = new Highcharts.StockChart({
          chart : {
              renderTo : 'container'
          },
  
          rangeSelector : {
              selected : 1
          },
  
          title : {
              text : 'AAPL Stock Price'
          },
  
          series : [{
              name : 'AAPL',
              data : data,
              type : 'column',
              tooltip: {
                  yDecimals: 2
              },
              dataGrouping: {
                  units: ['day', [1]]
              }
          }]
      });
  });
  </code></pre>
  
  <p><a href="http://jsfiddle.net/ndkKz/" rel="nofollow">Which works fine</a>. Displays nice two columns. Problem is that if I duplicate second line of data, so I will have:</p>
  
  <pre><code>             [1315522800001, 9],
               [1315522800001, 9],
               [1317596400000, 3],
  </code></pre>
  
  <p>I don't get expected result. What's even worse browser eats all my RAM (tested on Opera and Firefox on Linux and Safari on Mac) and displays almost nothing.</p>
  
  <p>My question is what am I doing wrong here? What I don't know?
  All more complex examples from website work, but I cannot seem to find any particular problem with my code.</p>