title: How to add additional row in yii cgridview <thead></thead>
body: <p>I want to add additional row like   and , thead-2 has empty cells. These empty cells will be used to 'collspan' in my table.</p>
  
  <p>This is my table now:</p>
  
  <p><a href="https://dl.dropboxusercontent.com/u/10002593/Screenshot%20from%202013-12-31%2008%3A43%3A55.png" rel="nofollow">https://dl.dropboxusercontent.com/u/10002593/Screenshot%20from%202013-12-31%2008%3A43%3A55.png</a></p>
  
  <p>And so I would like to achieve the effect:</p>
  
  <p><a href="https://dl.dropboxusercontent.com/u/10002593/output.jpg" rel="nofollow">https://dl.dropboxusercontent.com/u/10002593/output.jpg</a></p>
  
  <p>Thanks.,</p>