Fix bug #12277 with incomplete redisplay of the vertical border between windows.

 src/dispnew.c (update_window_line): When the left margin area of a
 screen line is updated, set the redraw_fringe_bitmaps_p flag of
 that screen line.

2 files changed, 11 insertions, 0 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index ae99fcc138d..e336e3dfe89 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,9 @@
+2012-09-09  Eli Zaretskii  <eliz@gnu.org>
+
+        * dispnew.c (update_window_line): When the left margin area of a
+        screen line is updated, set the redraw_fringe_bitmaps_p flag of
+        that screen line.  (Bug#12277)
+
 2012-09-09  Paul Eggert  <eggert@cs.ucla.edu>
 
         Assume C89 or later for math functions (Bug#12381).
diff --git a/src/dispnew.c b/src/dispnew.c
index 85b3254aae3..fae415dcaf2 100644
--- a/src/dispnew.c
+++ b/src/dispnew.c
@@ -3951,6 +3951,11 @@ update_window_line (struct window *w, int vpos, bool *mouse_face_overwritten_p)
         {
           changed_p = 1;
           update_marginal_area (w, LEFT_MARGIN_AREA, vpos);
+          /* Setting this flag will ensure the vertical border, if
+             any, between this window and the one on its left will be
+             redrawn.  This is necessary because updating the left
+             margin area can potentially draw over the border.  */
+          current_row->redraw_fringe_bitmaps_p = 1;
         }
 
       /* Update the display of the text area.  */