title: ng-click not working with ng-if
body: <p><strong>Why does the second button not work, when ng-if is used?</strong></p>
  
  <p>I want to realize a button that is present only when the model value is set / not ""/ not null.</p>
  
  <p>Template:</p>
  
  <pre><code>&lt;input type="text" ng-model="blub"/&gt;
  &lt;br/&gt;
  &lt;button ng-click="blub = 'xxxx'"&gt;X&lt;/button&gt;
  &lt;br/&gt;
  &lt;button ng-click="blub = 'yyyy'" ng-if="blub.length"&gt;Y&lt;/button&gt;
  </code></pre>
  
  <p>Controller:</p>
  
  <pre><code>angular.module('test', [])
  .controller('Main', function ($scope) {
      // nothing to do here
  });
  </code></pre>
  
  <p>To play around: <kbd><a href="http://jsfiddle.net/ufcpvdL7/1/">JSFiddle</a></kbd></p>