private static void HighlightFoundWindow(IntPtr hWnd)
{
var r = new WinApi.RECT();
WinApi.GetClientRect(hWnd, out r);
using (var g = Graphics.FromHwnd(hWnd))
g.DrawRectangle(new Pen(Color.ForestGreen, 3),
r.Left, r.Top, r.Right - 1, r.Bottom - 1);
}