title: chart js tooltip how to control the data that show
body: <p>I'm using chart.js plugin and using a group chart by bar view.
  when i hover a group of bars i can see a tooltip that show me the data of this bars.
  but i what to change the tooltip to show my only single data when I'll hover the bar data.
  and I what to show diffrent data info.
  <a href="http://jsfiddle.net/sGTA9/2/">jsfiddle example</a></p>
  
  <pre><code>    var ctx = document.getElementById("errorChart").getContext("2d");
  var data = {
      labels: ["January", "February", "March", "April", "May", "June", "July"],
      datasets: [
          {
              label: "My First dataset",
              fillColor: "rgba(220,220,220,0.5)",
              strokeColor: "rgba(220,220,220,0.8)",
              highlightFill: "rgba(220,220,220,0.75)",
              highlightStroke: "rgba(220,220,220,1)",
              data: [65, 0, 0, 0, 0, 0, 0]
          },
          {
              label: "My Second dataset",
              fillColor: "rgba(151,187,205,0.5)",
              strokeColor: "rgba(151,187,205,0.8)",
              highlightFill: "rgba(151,187,205,0.75)",
              highlightStroke: "rgba(151,187,205,1)",
              data: [28, 48, 40, 19, 86, 27, 90]
          }
      ]
  };
  var myBarChart = new Chart(ctx).Bar(data);
  </code></pre>