ModernWPF.Internal.LegacyBorderManager.UpdateFrame C# (CSharp) Method

        static void UpdateFrame(IntPtr handle)
        {
            SetRegion(handle, 0, 0, true);

            // SWP_DRAWFRAME makes window bg really transparent (visible during resize) and not black
            User32.SetWindowPos(handle, IntPtr.Zero, 0, 0, 0, 0,
                SetWindowPosOptions.SWP_NOOWNERZORDER |
                SetWindowPosOptions.SWP_DRAWFRAME |
                SetWindowPosOptions.SWP_NOACTIVATE |
                SetWindowPosOptions.SWP_NOZORDER |
                SetWindowPosOptions.SWP_NOMOVE |
                SetWindowPosOptions.SWP_NOSIZE);

            //var result = User32.SetClassLong(handle, CommonWin32.WindowClasses.ClassLong.GCLP_HBRBACKGROUND, GetSysColorBrush(COLOR_WINDOW));
        }