title: How to sort the grouped rows in AngularJS ui-grid?
body: <p>How can I sort the grouped rows in AngularJS ui-grid?</p>
  
  <p>Like in the official <a href="http://ui-grid.info/docs/#/tutorial/209_grouping" rel="noreferrer">grouping tutorial</a>, in the demo grid, if I were to sort the balance column ascending, none of the grouped rows would change, but the sorting was actually taking effect on the rows under each grouped rows. Like the image showing below. </p>
  
  <p>The question is, how can I make it work so that the sorting can work on the grouped rows. </p>
  
  <p><img src="https://i.stack.imgur.com/EAUNx.png" alt="enter image description here"></p>
  
  <p>I tried to set the groped columns' sort priorities to higher than 0, but that seems doesn't work. </p>