title: Reference custom resource defined in another xaml file
body: <p>I am trying to create a new resource in one xaml file and reference it in another xaml file.
  i.e I define    </p>
  
  <pre><code>&lt;Window.Resources&gt;
      &lt;ImageBrush x:Key="TileBrush" TileMode="Tile" ViewportUnits="Absolute" Viewport="0 0 32 32" ImageSource="MyImageButton.png" Opacity="0.3"&gt;
      &lt;/ImageBrush&gt;
  &lt;/Window.Resources&gt;
  </code></pre>
  
  <p>And attempt to use it in another xaml file by</p>
  
  <pre><code>&lt;Grid&gt;
      &lt;Button Background="{StaticResource TileBrush}" Margin="5" Padding="5" FontWeight="Bold" FontSize="14"&gt;
          A Tiled Button
      &lt;/Button&gt;
  &lt;/Grid&gt;
  </code></pre>
  
  <p>However I get the error <em>"StaticResource reference 'TileBrush' was not found."</em>
  I can reference the resource from the same xaml file but don't know how to do so from another file.</p>