title: Issue capturing a bitmap using window handle in windows 8
body: <p>This is my code which works completely fine on windows 7:</p>
  
  <pre><code>        [DllImport("user32.dll")]
          public static extern bool PrintWindow(IntPtr hwnd, IntPtr hdcBlt, uint nFlags);
  
          [DllImport("user32.dll")]
          public static extern IntPtr GetWindowDC(IntPtr hWnd);
  
          public static Bitmap CaptureWindow(IntPtr hWnd) {
              Rectangle rctForm = Rectangle.Empty;
  
              using (Graphics grfx = Graphics.FromHdc(DLLImport.GetWindowDC(hWnd))) {
                  rctForm = Rectangle.Round(grfx.VisibleClipBounds);
              }
  
              Bitmap pImage = new Bitmap(rctForm.Width, rctForm.Height);
              Graphics graphics = Graphics.FromImage(pImage);
              IntPtr hDC = graphics.GetHdc();
  
              try {
                  DLLImport.PrintWindow(hWnd, hDC, (uint)0);
              } finally {
                  graphics.ReleaseHdc(hDC);
              }
  
              return pImage;
          }
  </code></pre>
  
  <p>The issue I'm having is that on Windows 8 it appears to generate a completely blank Bitmap (the dimensions are correct though). Does anyone know what could be going on?</p>