title: Angular error message flashes very briefly on screen when using angular-ui's ui-date datepicker
body: <p>I'm running into an issue where ng-message is flashing the 'required' error message despite there being input in the input box.  What happens is that it very briefly flashes the error message: "THIS FIELD IS REQUIRED (ALL IN CAPS TO MAKE IT EASIER TO SEE IT FLASH BY!)" on the screen before it disappears right away.  Sorry for the caps but I wanted to make the message easier to see before it disappears.</p>
  
  <p>Here is a <a href="https://plnkr.co/edit/jPAALWTtgE6kOkN6u0JV?p=preview" rel="noreferrer">link to my plunker</a>.  Please enter any input and then click elsewhere on the page so that the input field loses focus.  <em>Pay attention because the error message in red will flash by briefly then disappear</em>.  If you didn't notice the message flash by quickly, you will have to reload the page again to see it happen again.    </p>
  
  <p>Why is this happening?  I believe it has something to do with ui-date because I'm not able to replicate the problem without ui-date.</p>
  
  <p>Here's a snippet of the code:</p>
  
  <pre><code>&lt;form name="reportform" ng-submit="process_form()" novalidate &gt;
    &lt;input name="startdate" placeholder="Enter a start date" ui-date ng-model="startdatevalue"  required&gt;
    &lt;ng-messages ng-if='reportform.startdate.$touched' for="reportform.startdate.$error"&gt;
      &lt;ng-message when="required" class="error-message"&gt;
        THIS FIELD IS REQUIRED (ALL IN CAPS TO MAKE IT EASIER TO SEE IT FLASH BY!)
      &lt;/ng-message&gt;
    &lt;/ng-messages&gt;
    &lt;button ng-disabled="reportform.$invalid" type="submit"&gt;
      Submit Query
    &lt;/button&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>Thanks for your help.</p>