title: jqPlot Pie Chart Tooltips Not Appearing
body: <p>My pie charts are rendering properly, however tooltips are not appearing when hovering over the slices when attempting to use the highlighter plugin for the tooltips.
  Please take a look at the options I'm setting and let me know if I'm missing something obvious, thanks.</p>
  
  <p>I've included the following relevant js files:</p>
  
  <ul>
  <li>jquery.min.js</li>
  <li>jquery.jqplot.min.js</li>
  <li>jqplot.pieRenderer.min.js</li>
  <li>jqplot.highlighter.min.js</li>
  </ul>
  
  <p>Here are the options I'm setting:</p>
  
  <pre><code>var options = {
      seriesDefaults: {
          seriesColors: ['#00809d', '#c22a33'],
          renderer: jQuery.jqplot.PieRenderer,
          rendererOptions: {
              showDataLabels: true,
              dataLabels: 'label',
              dataLabelPositionFactor: .45,
              sliceMargin: 1,
              drawBorder: false,
              startAngle: -90,
              highlightMouseOver: true
          },
          highlighter: {
              show: true,
              showTooltip: true,
              formatString:'%s',
              tooltipLocation: 'ne',
              useAxesFormatters: false
          },
          shadow: false
      },  
      legend: { show:false },
      grid: {
          drawGridlines: false,  
          borderColor: 'transparent',
          shadow: false,
          drawBorder: false,
          shadowColor: 'transparent',
          background: 'transparent'
      }
  };
  </code></pre>