title: Design-time-only background color in WPF?
body: <p>In WPF XAML there is the convenient <code>DesignHeight</code> and <code>DesignWidth</code>, for instance in code as</p>
  
  <pre><code>&lt;UserControl ... d:DesignHeight="500" d:DesignWidth="500" ... /&gt;
  </code></pre>
  
  <p>which is great because I can build the layout with a <em>representative</em>, but <em>not locked-in</em>, control size.</p>
  
  <p>However, I'm often building dark UIs, where labels and so forth need to be white, but my controls still need a transparent background color. This creates a design-time inconvenience because white seems to be the default background color for transparent controls in the designer, leading to unreadable white-on-white labels.</p>
  
  <p>Is there a way or strategy for setting the design-time background color, with similar convenience as DesignHeight/DesignWidth?</p>