Fix redrawing of mode lines when exposed (Bug#19721)

 src/dispnew.c (adjust_glyph_matrix): Set the update_mode_line flag
 of the window whose current glyph matrix was resized, which
 disables the mode-line row as side effect.
 src/xdisp.c (redisplay_window): Don't avoid redisplay of a window
 whose update_mode_line flag is set.

3 files changed, 16 insertions, 0 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 829eb25f4d9..c8ea8b586ed 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,12 @@
+2015-02-02  Eli Zaretskii  <eliz@gnu.org>
+
+        * dispnew.c (adjust_glyph_matrix): Set the update_mode_line flag
+        of the window whose current glyph matrix was resized, which
+        disables the mode-line row as side effect.
+
+        * xdisp.c (redisplay_window): Don't avoid redisplay of a window
+        whose update_mode_line flag is set.  (Bug#19721)
+
 2015-01-30  Eli Zaretskii  <eliz@gnu.org>
 
         * dispextern.h (FACE_FOR_CHAR): Fix the commentary.
diff --git a/src/dispnew.c b/src/dispnew.c
index f73ea58b7f3..6517c9b5d19 100644
--- a/src/dispnew.c
+++ b/src/dispnew.c
@@ -570,6 +570,12 @@ adjust_glyph_matrix (struct window *w, struct glyph_matrix *matrix, int x, int y
               for (i = 0; i < matrix->nrows; ++i)
                 matrix->rows[i].enabled_p = false;
             }
+          /* We've disabled the mode-line row, so force redrawing of
+             the mode line, if any, since otherwise it will remain
+             disabled in the current matrix, and expose events won't
+             redraw it.  */
+          if (WINDOW_WANTS_MODELINE_P (w))
+            w->update_mode_line = 1;
         }
       else if (matrix == w->desired_matrix)
         {
diff --git a/src/xdisp.c b/src/xdisp.c
index b1125d324c2..2ebf06d5c34 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -15964,6 +15964,7 @@ redisplay_window (Lisp_Object window, bool just_this_one_p)
   if (!just_this_one_p
       && REDISPLAY_SOME_P ()
       && !w->redisplay
+      && !w->update_mode_line
       && !f->redisplay
       && !buffer->text->redisplay
       && BUF_PT (buffer) == w->last_point)