title: Highcharts column + line combination chart with multiple series. Issue aligning line over the column
body: <p>I have a multi-series column chart (3 in this case). I wanted to overlay a line over the columns across all series. So i created a 3 more Line series' with the same column series data. This works perfectly when there is only one column and line series. With more than one series, the line renders at the center of the category, instead of showing up on the corresponding column (Note: left shifting the line will work, but i dont know how).</p>
  
  <p>Link to JSFiddle: <a href="http://jsfiddle.net/Wm6dU/7/" rel="nofollow">http://jsfiddle.net/Wm6dU/7/</a></p>
  
  <pre><code>$(function () {
      $('#container').highcharts({
          chart: {
              type: 'column'
          },
          title: {
              text: "Column Line Combo"
          },
          xAxis: {
              categories: [
                  "Cat 1",
                  "Cat 2",
                  "Cat 3"],
          },
          yAxis: {
              title: {
                  text: 'USD'
              }
          },
          series: [{
              name: "Revenue",
              data: [
              49.9,
              71.5,
              106.4],
              type: "column"
          }, {
              name: "Revenue",
              data: [
              49.9,
              71.5,
              106.4],
              type: "line"
          }, {
              name: "Cost of goods sold",
              data: [
              83.6,
              78.8,
              98.5],
              type: "column"
          }, {
              name: "Cost of goods sold",
              data: [
              83.6,
              78.8,
              98.5],
              type: "line"
          }, {
              name: "Operating Expenses",
              data: [
              48.9,
              38.8,
              39.3],
              type: "column"
          }, {
              name: "Operating Expenses",
              data: [
              48.9,
              38.8,
              39.3],
              type: "line"
          }]
      });
  });
  </code></pre>
  
  <p>Thanks.</p>