title: ui-grid symbols issue
body: <p>I am using AngularJs ui-grid <a href="http://ui-grid.info/" rel="noreferrer">http://ui-grid.info/</a>.</p>
  
  <p>While implementing, I get something which you can see in the following img in right corner of the cell instead of dropdown symbols.</p>
  
  <p><img src="https://i.stack.imgur.com/hex2T.png" alt="enter image description here"></p>
  
  <p>Which files to include to solve this bug?</p>