title: error message in the form validation is not showing as expected
body: <p>I am working on angularjs and bootstrap application. I'm trying to validate the simple form, when user click on submit button all the fields in the from should have a value.</p>
  
  <p>Please find the demo : <a href="https://plnkr.co/edit/aHtODbTTFZfpIRO3BWhf?p=preview" rel="nofollow noreferrer">https://plnkr.co/edit/aHtODbTTFZfpIRO3BWhf?p=preview</a>
  In the demo above, when user click on submit button with out selecting the checkbox , an error message is shown 'Please Select the Color..' , after the error message is shown select the checkbox and click on submit button still the error message is displayed. Any inputs on this?</p>
  
  <p>html code:</p>
  
  <pre><code>&lt;form name="myForm" ng-controller="ExampleController"&gt;
     &lt;div&gt;Select Color : &lt;/div&gt;
        &lt;label name="color" ng-repeat="color in colorNames" class="checkbox-inline"&gt;
  &lt;input ng-required="selectedColor.length === 0" oninvalid="this.setCustomValidity('Please select the color..')" type="checkbox" name="color" value="{{color}}" ng-checked="selectedColor.indexOf(color) &gt; -1" ng-click="userSelection(color)"&gt;                        &lt;!--&lt;input type="checkbox" name="color" value="{{color}}" ng-checked="selectedColor.indexOf(color) &gt; -1" ng-click="userSelection(color)"&gt; {{color}}--&gt;
       {{color}}       &lt;br&gt;       &lt;/label&gt;
  
              &lt;div class=""&gt;
                  &lt;div style="color: black;"&gt;Username : &lt;/div&gt;
                 &lt;input type="text" name="user" value="" required&gt;
                  &lt;div ng-show="myForm.$submitted || myForm.user.$touched"&gt;
                      &lt;p class="error-mesg" ng-show="myForm.user.$error.required"&gt;The Username is required&lt;/p&gt;
                  &lt;/div&gt;
              &lt;/div&gt;            
               &lt;button type="submit" class="btn btn-primary" ng-click="submitForm(myForm)"&gt;Submit&lt;/button&gt;
   &lt;/form&gt;
  </code></pre>