title: Retrieving size of Windows 10 shadowing border
body: <p>We have an application that draws a colored border around specific application windows and dialogs.</p>
  
  <p>We use <a href="https://msdn.microsoft.com/en-us/library/windows/desktop/ms633519(v=vs.85).aspx" rel="nofollow">GetWindowRect</a> to get the rectangle of an application window. But on Windows 10 this function includes the shadowing border resulting in a large gap between our colored border and the application window. So we need to compensate for the shadowing border.</p>
  
  <p>Which API can we use to determine the width of the shadowing border around application windows and dialogs in Windows 10?</p>