title: WPF Popup event handling - How to get triggered when Popup opens
body: <p>I created a WPF Popup which contains a grid with border.
  There is some animation associated with the border which I want to be triggered every time the Popup opens.</p>
  
  <p>Currently the code is like this</p>
  
  <pre><code>&lt;Popup x:Name="myPopUp" &gt;
    &lt;Border x:Name="myBorder" &gt;
      &lt;Border.Triggers&gt;
                 &lt;EventTrigger RoutedEvent="Popup.Loaded"&gt;
                          &lt;BeginStoryboard&gt;
                              &lt;Storyboard&gt;
                                  &lt;DoubleAnimation
                                      Storyboard.TargetName="myBorder" 
                                      Storyboard.TargetProperty="Height"
                                      From="10" To="255" Duration="0:0:0.20" /&gt;                      
                              &lt;/Storyboard&gt;
                          &lt;/BeginStoryboard&gt;
                      &lt;/EventTrigger&gt;
       &lt;/Border.Triggers&gt;
       &lt;Grid /&gt;
     &lt;/Border&gt;
  &lt;/Popup&gt;
  </code></pre>
  
  <p>As per the code the border shows up the animation for the first time the popup opens. 
  What change do I need to make to trigger the border animation every time the Popup opens?</p>