public static extern IntPtr WindowFromPoint(POINT p);
public static extern Boolean ClientToScreen(IntPtr hWnd, ref POINT point);
public static extern Boolean UpdateLayeredWindow( IntPtr hWnd, IntPtr hdcDst, ref POINT pptDst, ref SIZE psize, IntPtr hdcSrc, ref POINT pptSrc, Int32 crKey, ref BLENDFUNCTION pblend, Int32 dwFlags );
public static extern IntPtr ChildWindowFromPointEx(IntPtr hwndParent, POINT pt, uint flags);
public static extern Boolean ScreenToClient(IntPtr hWnd, ref POINT lpPoint);
public static extern Boolean GetCaretPos(out POINT lpPoint);
public static extern bool GetCaretPos(out POINT lpPoint);