title: Grouped Header Column size
body: <p>I have a grouped header grid. The grid definition can be found in the fiddle <a href="http://jsfiddle.net/7sZge/" rel="nofollow noreferrer">here</a>.</p>
  
  <p>The result looks like this.</p>
  
  <p><img src="https://i.stack.imgur.com/bIzug.png" alt="enter image description here"></p>
  
  <p>I want all the columns to be of equal space, including the ones inside the grouped header. What am I doing wrong?</p>