title: Angular ng model requires 2 click when using ng true and ng false
body: <p>I'm using checkbox with ng model and ng-true-value and ng-false-value.
  It works fine but when its value comes 1 and it checked by default then it will take 2 clicks to change the value.</p>
  
  <p>Is there any way to do it with first click</p>
  
  <p>Code Example :</p>
  
  <pre><code>&lt;input type="checkbox" ng-checked="CreateUpdateCat.IsDiscussionAllowed=='1'" ng-model="CreateUpdateCat.IsDiscussionAllowed" ng-true-value="1" ng-false-value="2" &gt;
  </code></pre>
  
  <p>Controller Code :</p>
  
  <pre><code>angular.forEach($scope.CategoryData,function(v,k){
                          if(v.id == id)
                          {
  $scope.CreateUpdateCat = {IsDiscussionAllowed:v.IsDiscussionAllowed,Name:v.Name};
  };
  });
  </code></pre>
  
  <p>here is plunkr url : <a href="https://plnkr.co/edit/JApepZfvNrlqDj9vine0?p=preview" rel="nofollow noreferrer">https://plnkr.co/edit/JApepZfvNrlqDj9vine0?p=preview</a>
  value is 1 by default but checkbox is not showing checked</p>