message: Update window_w32.cpp
diff: @@ -250,13 +250,13 @@ CV_IMPL int cvInitSystem( int, char** )
  wndc.lpszMenuName = highGUIclassName;
  wndc.hIcon = LoadIcon(0, IDI_APPLICATION);
  wndc.hCursor = (HCURSOR)LoadCursor(0, (LPSTR)(size_t)IDC_CROSS );
  - wndc.hbrBackground = (HBRUSH)GetStockObject(GRAY_BRUSH);
  + wndc.hbrBackground = (HBRUSH)GetStockObject(DKGRAY_BRUSH);
  RegisterClass(&wndc);
  wndc.lpszClassName = mainHighGUIclassName;
  wndc.lpszMenuName = mainHighGUIclassName;
  - wndc.hbrBackground = (HBRUSH)GetStockObject(GRAY_BRUSH);
  + wndc.hbrBackground = (HBRUSH)GetStockObject(DKGRAY_BRUSH);
  wndc.lpfnWndProc = MainWindowProc;
  RegisterClass(&wndc);
  