title: Extjs 4 grid mouseover show full cell value
body: <p>I've got a grid with a long string in one of the columns. I would like the full string to appear when the user mouses over any cell in this column.</p>
  
  <p>So far I have it working where a tooltip pops up for any cell in this column but they don't display the text. The tooltip always just says "Icon Tip".</p>
  
  <p><strong>How do I get the qtip to display the variable val instead of the string "Icon Tip"?</strong></p>
  
  <pre><code>Ext.define('AM.view.user.List' , {
      extend: 'Ext.grid.Panel',
      .......
      initComponent: function() {
          function renderTip(val, meta, rec, rowIndex, colIndex, store) {
              meta.tdAttr = 'data-qtip="Icon Tip"';
              return val;
          };
          this.columns = [
              {header: 'First Name', dataIndex: 'FirstName', width: 75},
              {header: 'Last Name', dataIndex: 'Last', width: 75},
              {header: 'Perm', dataIndex: 'Perm', width: 75},
              {header: 'Comment', dataIndex: 'Comments', width: 150, renderer: renderTip}
          ];
          this.callParent(arguments);
      }
  });
  </code></pre>