title: FireFox editableCellTemplate only enabling editing one time
body: <p>In Firefox, we have an editableCellTemplate of:</p>
  
  <pre><code>&lt;input type="number" ng-class="\'colt\' + col.index" ng-input="COL_FIELD" ng-model="COL_FIELD" /&gt;
  </code></pre>
  
  <p>The first time a user clicks, it allows him to modify the cell. Any subsequent attempts do not enter edit mode. We are currently using version 2.0.7 of the grid. However, it works fine in Chrome and IE.</p>
  
  <p>There is an error in the Firefox console once trying to edit the same cell:
  TypeError: current is null angular.js:9186</p>
  
  <p>Here is a jsfiddle to illustrate the problem in Firefox: Try modifying the 'age' column.</p>
  
  <p><a href="http://jsfiddle.net/zlaja1983/38hPb/" rel="nofollow">http://jsfiddle.net/zlaja1983/38hPb/</a></p>