title: Mahapps title bar change color when application lost focus
body: <p>I define Title bar color:</p>
  
  <pre><code>&lt;Controls:MetroWindow
  ...
  
  WindowTitleBrush="Red"
  </code></pre>
  
  <p>But when the application lost focus this color always changed into <code>Gray</code>, is it possible to stop it ?</p>