Fix bug #18490 with redisplay of other windows showing a narrowed buffer.

 src/xdisp.c (redisplay_internal): Force redisplay of all windows
 that show a buffer whose narrowing has changed.

src/ChangeLog

+2014-09-18  Eli Zaretskii  <eliz@gnu.org>
+
+	* xdisp.c (redisplay_internal): Force redisplay of all windows
+	that show a buffer whose narrowing has changed.  (Bug#18490)
+
 2014-09-16  Eli Zaretskii  <eliz@gnu.org>
 
 	* xterm.c (x_draw_hollow_cursor, x_draw_bar_cursor):

src/xdisp.c

@@ -13598,6 +13598,12 @@ redisplay_internal (void)
       if (mode_line_update_needed (w))
 	w->update_mode_line = 1;
+
+      /* If reconsider_clip_changes above decided that the narrowing
+	 in the current buffer changed, make sure all other windows
+	 showing that buffer will be redisplayed.  */
+      if (current_buffer->clip_changed)
+	bset_update_mode_line (current_buffer);
     }
   /* Normally the message* functions will have already displayed and