Re: [simon.marshall@misys.com: Possible mouse-face redisplay glitch]

[Chong Yidong <cyd@stupidchicken.com>]

Richard Stallman <rms@gnu.org> writes:

> First generate a calendar in the lower window with:
>
> M-x calendar RET
>
> Put mouse over Jan 3 entry such that its mouse-face text property is active
> and:
>
> <
>
> For me, the position under the mouse (ie, the non-entry above Dec 6 entry)
> still appears highlighted in mouse-face.  A C-l clears the highlighting.

This bug was introduced by the following change:

2006-10-06  Kim F. Storm  <storm@cua.dk>

	* xdisp.c (pos_visible_p): Fix value when EOB is visible.

*** emacs/src/xdisp.c	2006/10/01 16:44:43	1.1123
--- emacs/src/xdisp.c	2006/10/06 13:30:45	1.1124
***************
*** 1346,1352 ****
        it2 = it;
        if (IT_CHARPOS (it) < ZV && FETCH_BYTE (IT_BYTEPOS (it)) != '\n')
  	move_it_by_lines (&it, 1, 0);
!       if (charpos < IT_CHARPOS (it))
  	{
  	  visible_p = 1;
  	  move_it_to (&it2, charpos, -1, -1, -1, MOVE_TO_POS);
--- 1346,1353 ----
        it2 = it;
        if (IT_CHARPOS (it) < ZV && FETCH_BYTE (IT_BYTEPOS (it)) != '\n')
  	move_it_by_lines (&it, 1, 0);
!       if (charpos < IT_CHARPOS (it)
! 	  || (it.what == IT_EOB && charpos == IT_CHARPOS (it)))
  	{
  	  visible_p = 1;
  	  move_it_to (&it2, charpos, -1, -1, -1, MOVE_TO_POS);

Kim, do you remember what the rationale for this change was, and can
you think of why this is causing the problem?