title: Knockout - validation showing same error message twice
body: <p>I am using knockout validation plugin to validate a simple form field , validation is working but it is showing same error message twice below text box.</p>
  
  <p>my code follows 
  <br> JS viewmodel</p>
  
  <pre><code>    $(document).ready(function () {
     ko.validation.registerExtenders();
      ko.validation.configure({
          registerExtenders: true,
          messagesOnModified: false,
          insertMessages: false,
          parseInputAttributes: true,
          messageTemplate: null
      });
      ko.validation.init();
  
      var vm = new viewmodel();
      ko.applyBindings(vm, document.getElementById("div"));
  });
  that.formField= ko.observable(vm.formField).extend({ required:  true, minLength: 5, maxLength: 50 });
  
  
  **html**
  
      &lt;p&gt;
         &lt;label class="field-label"&gt;Who provides your service?&lt;/label&gt;
          &lt;input name="txtService" id="txtInsservice"  data-bind="value: formField, valueUpdate: 'keyup'" class="field-stretch" type="text" maxlength="50" /&gt; 
              &lt;/p&gt;
  </code></pre>
  
  <p>Anything wrong with this?</p>