title: knockout Validation message displaying twice?
body: <p>I been used to do validation using knockout validation plugin and all of a sudden i am facing a issue i am unable to get rid of .</p>
  
  <p><strong>Html onLoad :</strong></p>
  
  <pre><code>&lt;input class="form-control" type="text" data-bind="value:$data.Name"/&gt;
  &lt;span class="required" style="display: none;"&gt;&lt;/span&gt;
  &lt;span class="required" style="display: none;"&gt;&lt;/span&gt;
  </code></pre>
  
  <p><strong>ViewModel:</strong></p>
  
  <pre><code>function details() {
      var self =this;
      self.Name = ko.observable("");
      self.Validation = ko.validatedObservable([
          self.Name.extend({ number: true })
      ]);
  }
  </code></pre>
  
  <p>When i removed <code>self.Name.extend</code> i get <code>no</code> span tags onLoad but if i keep it then i get two span tags and because of that i get same error messages displaying twice under control like <code>this field is required</code> &amp; <code>this field is required</code> .</p>
  
  <p>I also debugged and checked the function is excecuting only once .</p>
  
  <p>I refered <a href="https://stackoverflow.com/questions/22399928/knockout-validation-showing-same-error-message-twice">this</a> but i can't fix my issue .</p>
  
  <p>I hope someone can show light on this issue .</p>