title: Knockout Validation with throttle
body: <p>I just noticed that using the throttle extender causes Knockout Validation to stop working. Is there a way around this problem?</p>
  
  <pre><code>var viewModel = {
      label1: ko.observable('label1').extend({required: true}),
      label2: ko.observable('label2').extend({required: true, throttle: 1}),
  };
  
  ko.applyBindings(viewModel);
  </code></pre>
  
  <p>jsFiddle: <a href="http://jsfiddle.net/rWqkC/" rel="nofollow">http://jsfiddle.net/rWqkC/</a></p>