title: WPF Background change of Border OnMouseDown
body: <p>I'm trying to change the background of a border on left mousebutton down. Button I don't get it. Of Course my gradient has 3 stops.</p>
  
  <p><em>Eventtrigger:</em></p>
  
  <pre><code>&lt;EventTrigger  RoutedEvent="UIElement.PreviewMouseLeftButtonDown" SourceName="border"&gt;
      &lt;BeginStoryboard x:Name="MouseDown_BeginStoryboard" Storyboard="{StaticResource OnMouseDown}"/&gt;
  &lt;/EventTrigger&gt;
  </code></pre>
  
  <p><em>StoryBoard:</em></p>
  
  <pre><code>&lt;Storyboard x:Key="OnMouseDown"&gt;
      &lt;ColorAnimation Duration="0:0:0.15" Storyboard.TargetName="border" Storyboard.TargetProperty="Background.GradientStops[0].Color" To="Red" /&gt;
      &lt;ColorAnimation Duration="0:0:0.15" Storyboard.TargetName="border" Storyboard.TargetProperty="Background.GradientStops[1].Color" To="Red" /&gt;
      &lt;ColorAnimation Duration="0:0:0.15" Storyboard.TargetName="border" Storyboard.TargetProperty="Background.GradientStops[2].Color" To="Red" /&gt;
  &lt;/Storyboard&gt;
  </code></pre>
  
  <p>If anybody sees the mistake please tell me ;)</p>