title: Duplicated scope ngSwitch
body: <p>I have a directive - popup, that when activated it switches to its content.</p>
  
  <p>Using:</p>
  
  <pre><code> &lt;div  my-popup="popup"&gt;&lt;/div&gt; 
  </code></pre>
  
  <p>Popup:</p>
  
  <p>
          </p>
  
  <pre><code>    &lt;div ng-switch-when="true"&gt;Content&lt;/div&gt; 
  </code></pre>
  
  <p>
  This poup has a function, that parent can call.</p>
  
  <pre><code> scope.popup = { id: 'ddd', fn: function () {} };
  </code></pre>
  
  <p>The problem is, that when I close and open popup, the fn function gets called 2 times, and if I close it again, and open it again, it gets called 3-times, .... n-times.</p>
  
  <p>So function gets called as manny times as the popup has been opened. How to fix this?</p>