private bool ClickOkButton(IntPtr hwnd)
        {
            // for debugging
            var info = new NativeWindowCalls.WINDOWINFO();

            info.cbSize = (uint)Marshal.SizeOf(info);
            NativeWindowCalls.GetWindowInfo(hwnd, ref info);
            string titleCheck = NativeWindowCalls.GetWindowText(hwnd);

            // verify
            if (hwnd != IntPtr.Zero)
            {
                // click ok
                NativeWindowCalls.SendMessage(hwnd, NativeWindowCalls.WmActivate, NativeWindowCalls.MaActivate, 0);
                NativeWindowCalls.SendMessage(hwnd, NativeWindowCalls.BtnClick, 0, 0);
                return(true);
            }

            return(false);
        }