6 months ago I reported bug #4426, that is, `posn-at-point' returns
incorrect value when header line is displayed. I've investigated this
bug and found the solution.

I describe again this bug:

   If header line is displayed, `posn-object-width-height' incorrectly
   returns the size of object in position different from specified one.

   For example, an expression

     (posn-object-width-height (posn-at-point (window-start)))

   must return the width and height of character on the top left corner
   of text area, but actually returns the ones on the beginning of
   header line.

It turned out that this problem occurs as a result of confusion between
it.vpos and MATRIX_ROW_VPOS in a function buffer_posn_from_coords
(included in dispnew.c).

So I wrote the small patch to fix this bug. Please check it.


IRIE Shinsuke