title: Changing ng-class not updating style?
body: <p>I have following code:</p>
  
  <p>Pug:</p>
  
  <pre><code>div(ng-class="('{{selectedMessageType}}' == 'incoming')?'messageTypeSelected':'messageTypeNotSelected'")
  </code></pre>
  
  <p>CSS:</p>
  
  <pre><code>.messageTypeSelected{
      background-color: #E8A83C;
      color: #ffffff;
  }
  
  .messageTypeNotSelected{
      background-color: #E4E4E4;
  }
  </code></pre>
  
  <p>JS:</p>
  
  <pre><code>$scope.selectedMessageType = 'incoming';
  $scope.changeMessageType = function(){
      ($scope.selectedMessageType ==  'incoming')?$scope.selectedMessageType = 'outgoing':$scope.selectedMessageType = 'incoming';
  };
  </code></pre>
  
  <p>My <code>{{selectedMessageType}}</code> is replaced correctly with the logic. I have also checked on it using Inspector on browser. However, the styling is not applied, when value is changed.</p>
  
  <p>What could be wrong in my code?</p>