Update frame title when scrolling the selected window

* src/window.c (wset_update_mode_line): New function, sets either the
window's update_mode_line flag or the global update_mode_lines
variable.
(Fset_window_start, set_window_buffer, window_scroll_pixel_based)
(window_scroll_line_based): Call it instead of only setting the
window's update_mode_line flag.

1 files changed, 20 insertions, 12 deletions

diff --git a/src/window.c b/src/window.c
index a8605ee628c..7c95ff9b16f 100644
--- a/src/window.c
+++ b/src/window.c
@@ -205,6 +205,20 @@ wset_combination (struct window *w, bool horflag, Lisp_Object val)
     w->horizontal = horflag;
 }
 
+static void
+wset_update_mode_line (struct window *w)
+{
+  /* If this window is the selected window on its frame, set the
+     global variable update_mode_lines, so that x_consider_frame_title
+     will consider this frame's title for rtedisplay.  */
+  Lisp_Object fselected_window = XFRAME (WINDOW_FRAME (w))->selected_window;
+
+  if (WINDOWP (fselected_window) && XWINDOW (fselected_window) == w)
+    update_mode_lines = 42;
+  else
+    w->update_mode_line = true;
+}
+
 /* True if leaf window W doesn't reflect the actual state
    of displayed buffer due to its text or overlays change.  */
 
@@ -1666,7 +1680,7 @@ overriding motion of point in order to display at this exact start.  */)
   w->start_at_line_beg = false;
   if (NILP (noforce))
     w->force_start = true;
-  w->update_mode_line = true;
+  wset_update_mode_line (w);
   /* Bug#15957.  */
   w->window_end_valid = false;
   wset_redisplay (w);
@@ -3271,14 +3285,8 @@ set_window_buffer (Lisp_Object window, Lisp_Object buffer,
   /* Maybe we could move this into the `if' but it's not obviously safe and
      I doubt it's worth the trouble.  */
   wset_redisplay (w);
-  /* If this window is the selected window on its frame, set the
-     global variable update_mode_lines, so that x_consider_frame_title
-     will consider this frame's title for rtedisplay.  */
-  Lisp_Object fselected_window = XFRAME (WINDOW_FRAME (w))->selected_window;
-  if (WINDOWP (fselected_window) && XWINDOW (fselected_window) == w)
-    update_mode_lines = 42;
-  else
-    w->update_mode_line = true;
+
+  wset_update_mode_line (w);
 
   /* We must select BUFFER to run the window-scroll-functions and to look up
      the buffer-local value of Vwindow_point_insertion_type.  */
@@ -4829,7 +4837,7 @@ window_scroll_pixel_based (Lisp_Object window, int n, bool whole, bool noerror)
                   set_marker_restricted (w->start, make_number (spos),
                                          w->contents);
                   w->start_at_line_beg = true;
-                  w->update_mode_line = true;
+                  wset_update_mode_line (w);
                   /* Set force_start so that redisplay_window will run the
                      window-scroll-functions.  */
                   w->force_start = true;
@@ -4977,7 +4985,7 @@ window_scroll_pixel_based (Lisp_Object window, int n, bool whole, bool noerror)
                                   IT_BYTEPOS (it));
       bytepos = marker_byte_position (w->start);
       w->start_at_line_beg = (pos == BEGV || FETCH_BYTE (bytepos - 1) == '\n');
-      w->update_mode_line = true;
+      wset_update_mode_line (w);
       /* Set force_start so that redisplay_window will run the
          window-scroll-functions.  */
       w->force_start = true;
@@ -5211,7 +5219,7 @@ window_scroll_line_based (Lisp_Object window, int n, bool whole, bool noerror)
 
       set_marker_restricted_both (w->start, w->contents, pos, pos_byte);
       w->start_at_line_beg = !NILP (bolp);
-      w->update_mode_line = true;
+      wset_update_mode_line (w);
       /* Set force_start so that redisplay_window will run
          the window-scroll-functions.  */
       w->force_start = true;