title: NetUIHWND and DirectUIHWND
body: <p>Using Spy++ tool, it seems that some Microsoft apps use <strong>NetUIHWND</strong> and <strong>DirectUIHWND</strong> window classes; e.g.: Word 2010's ribbon seems to be a NetUIHWND, instead Windows Live Messenger window seems to be a DirectUIHWND.</p>
  
  <p>These window classes seem to host kind of cool graphics (with shadows, gradients, etc.); is it possible to use these window classes in our own Win32 C++ apps? Is there any documentation about them?</p>