(Fdelete_other_windows): Set window's window_end_valid

to nil when changing the window's start.  Don't change the
window's start when its top position hasn't changed.  If we do,
this will set the window's optional_new_start, which act's like a
force_start during redisplay with C-x 1 M-> under particular
circumstances (see report from Per Starback to emacs-pretest-bug
from 2000-12-13.).
(Fdelete_other_windows): Set window's window_end_valid
to nil when changing the window's start.

diff --git a/src/window.c b/src/window.c
index 5d779026bad78728fc0acb8d489c02d5f55eac0d..16455f592200a95b7204b177b8d3c0391095bc1b 100644 (file)
--- a/src/window.c
+++ b/src/window.c
@@ -1691,8 +1691,7 @@ window_list_1 (window, minibuf, all_frames)
                 Qnil, look at just the selected frame;
                Qvisible, look at visible frames;
                a frame, just look at windows on that frame.
-   If MINI is non-zero, perform the operation on minibuffer windows too.
-*/
+   If MINI is non-zero, perform the operation on minibuffer windows too.  */
 
 enum window_loop
 {
@@ -1989,13 +1988,12 @@ value is reasonable when this function is called.")
 {
   struct window *w;
   int startpos;
-  int top;
+  int top, new_top;
 
   if (NILP (window))
     window = selected_window;
   else
     CHECK_LIVE_WINDOW (window, 0);
-
   w = XWINDOW (window);
 
   startpos = marker_position (w->start);
@@ -2011,7 +2009,9 @@ value is reasonable when this function is called.")
      on the frame.  But don't try to do this if the window start is
      outside the visible portion (as might happen when the display is
      not current, due to typeahead).  */
-  if (startpos >= BUF_BEGV (XBUFFER (w->buffer))
+  new_top = XFASTINT (w->top) - FRAME_TOP_MARGIN (XFRAME (WINDOW_FRAME (w)));
+  if (new_top != top
+      && startpos >= BUF_BEGV (XBUFFER (w->buffer))
       && startpos <= BUF_ZV (XBUFFER (w->buffer)))
     {
       struct position pos;
@@ -2023,6 +2023,7 @@ value is reasonable when this function is called.")
       pos = *vmotion (startpos, -top, w);
 
       set_marker_both (w->start, w->buffer, pos.bufpos, pos.bytepos);
+      w->window_end_valid = Qnil;
       w->start_at_line_beg = ((pos.bytepos == BEGV_BYTE
                               || FETCH_BYTE (pos.bytepos - 1) == '\n') ? Qt
                              : Qnil);