public static extern IntPtr GetWindowRect(IntPtr hwnd, ref NativeStructs.RECT rc);
        public void Highlight()
        {
            NativeStructs.RECT windowRect = new NativeStructs.RECT(0, 0, 0, 0);
            NativeMethods.GetWindowRect(handle, ref windowRect);

            IntPtr windowDC = NativeMethods.GetWindowDC(handle);
            if (windowDC != IntPtr.Zero)
            {
                Graphics graph = Graphics.FromHdc(windowDC, handle);
                graph.DrawRectangle(highlightPen, 1, 1, windowRect.Width - 2, windowRect.Height - 2);
                graph.Dispose();
                NativeMethods.ReleaseDC(handle, windowDC);
            }
        }