Fix bug #9324 with unwarranted repositioning of point.

 src/xdisp.c (redisplay_window): Don't force window start if point
 will be invisible in the resulting window.

2 files changed, 14 insertions, 1 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 149753a6749..9429064f371 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,8 @@
+2011-08-26  Eli Zaretskii  <eliz@gnu.org>
+
+        * xdisp.c (redisplay_window): Don't force window start if point
+        will be invisible in the resulting window.  (Bug#9324)
+
 2011-08-25  Eli Zaretskii  <eliz@gnu.org>
 
         * xdisp.c (compute_display_string_pos): Return 2 in DISP_PROP when
diff --git a/src/xdisp.c b/src/xdisp.c
index beb161f4ce4..08e14d71263 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -15099,6 +15099,7 @@ redisplay_window (Lisp_Object window, int just_this_one_p)
                || (XFASTINT (w->last_modified) >= MODIFF
                    && XFASTINT (w->last_overlay_modified) >= OVERLAY_MODIFF)))
     {
+      int d1, d2, d3, d4, d5, d6;
 
       /* If first window line is a continuation line, and window start
          is inside the modified region, but the first change is before
@@ -15120,7 +15121,14 @@ redisplay_window (Lisp_Object window, int just_this_one_p)
              compute_window_start_on_continuation_line.  (See also
              bug#197).  */
           && XMARKER (w->start)->buffer == current_buffer
-          && compute_window_start_on_continuation_line (w))
+          && compute_window_start_on_continuation_line (w)
+          /* It doesn't make sense to force the window start like we
+             do at label force_start if it is already known that point
+             will not be visible in the resulting window, because
+             doing so will move point from its correct position
+             instead of scrolling the window to bring point into view.
+             See bug#9324.  */
+          && pos_visible_p (w, PT, &d1, &d2, &d3, &d4, &d5, &d6))
         {
           w->force_start = Qt;
           SET_TEXT_POS_FROM_MARKER (startp, w->start);