title: Why should the host window not have CS_HREDRAW and CS_VREDRAW window styles?
body: <p>I was reading the SimpleRibbon sample application and I noticed a curious line in the source:</p>
  
  <pre><code>wcex.style          = 0;    // Don't use CS_HREDRAW or CS_VREDRAW with a Ribbon
  </code></pre>
  
  <p>I can't find any reference on MSDN or elsewhere that explains why these window classes shouldn't be used in a window that contains a ribbon. Does anyone know what this is all about?</p>
  
  <p>Cheers.</p>
  
  <p>Sample code: <a href="https://github.com/Microsoft/Windows-classic-samples/blob/master/Samples/Win7Samples/winui/WindowsRibbon/SimpleRibbon/CPP/SimpleRibbon.cpp" rel="nofollow noreferrer">GitHub Windows-classic-samples - SimpleRibbon.cpp</a></p>