title: How to get tooltip value from Google Scatter Charts selection
body: <p>I'm trying to get the tooltip of the selected entity on Google scatter chart. I create my datatable as following:</p>
  
  <pre><code>data = google.visualization.arrayToDataTable([
      ['Lines changed', 'TTL', 'Tooltip'],
      [25, 12, 'Text for first'],
      [34, 20, 'Text for second']
  ]);
  </code></pre>
  
  <p>and then I can access the selected one using </p>
  
  <pre><code>google.visualization.events.addListener(chart, 'select', function () {
      // when a point is selected
      var selection = chart.getSelection();
      console.log(data.getValue(selection[0].row, selection[0].column)); // this gives me the Y-value for that row and index
  });
  </code></pre>
  
  <p>Does anyone know how to get the tooltip text from that row and index instead of the Y-value?</p>
  
  <p><strong>EDIT</strong></p>
  
  <p>I <em>can</em> indeed add tooltips using the <code>arrayToDataTable()</code> method by setting column property like:</p>
  
  <pre><code>data.setColumnProperty(2, 'role', 'tooltip');
  </code></pre>
  
  <p>this makes third column (index 2) a tooltip. It's only that I can't (easily) add HTML to the tooltip using the method above. I had to revert to using <code>new google.visualization.DataTable()</code> instead.</p>