title: WPF Popup : open with animation
body: <p>I am using a wpf popup control.</p>
  
  <pre><code>&lt;Popup x:Name="tabHolder" IsOpen="False" 
      PopupAnimation="Slide" Placement="Bottom" 
      PlacementTarget="{Binding ElementName=mainWidgetWindow}"&gt;
      &lt;Grid Height="105" Width="315" /&gt;
  &lt;/Popup&gt;
  </code></pre>
  
  <p>Here I have set popup animation property to slide. But when it opens, it doesn't animate. Do I have to add any other configuration for popup to open with animation option slide?</p>
  
  <p>I am using .net framework version 3.5.</p>