HWND pascal WindowFromPoint(LPPOINT pPt)
 <MS-WINDOWS equivalent>

  This function searches for the highest window on the desktop which
contains this point.

Parameters
  pPt is a far pointer to a POINT structure containing the the 0-based
      row and col screen coordinates of the point we want to search for.

Returns
  The handle of the first window on the window list which contains
this point, or NULLHWND if no window contains this point.