[Emacs-diffs] emacs-26 24b5026: Fix redisplay when a window's scroll bar or fringes are changed

[Eli Zaretskii]

branch: emacs-26
commit 24b5026fb6b622966fd773178608617fa2f8add2
Author: Eli Zaretskii <address@hidden>
Commit: Eli Zaretskii <address@hidden>

    Fix redisplay when a window's scroll bar or fringes are changed
    
    * src/window.c (set_window_fringes, set_window_scroll_bars):
    Set windows_or_buffers_changed flag to cause immediate
    thorough redisplay of a window when scroll bars or fringes are
    changed.  (Bug#33694)
---
 src/window.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/src/window.c b/src/window.c
index 5d99098..6026313 100644
--- a/src/window.c
+++ b/src/window.c
@@ -7137,6 +7137,11 @@ set_window_fringes (struct window *w, Lisp_Object 
left_width,
       w->right_fringe_width = right;
       w->fringes_outside_margins = outside;
 
+      /* This is needed to trigger immediate redisplay of the window
+        when its fringes are changed, because fringes are redrawn
+        only if update_window is called, so we must trigger that even
+        if the window's glyph matrices did not change at all.  */
+      windows_or_buffers_changed = 35;
       return w;
     }
   else
@@ -7254,6 +7259,12 @@ set_window_scroll_bars (struct window *w, Lisp_Object 
width,
   wset_horizontal_scroll_bar_type (w, Qnil);
 #endif
 
+  /* This is needed to trigger immediate redisplay of the window when
+     scroll bars are changed, because scroll bars are redisplayed only
+     if more than a single window needs to be considered, see
+     redisplay_internal.  */
+  if (changed)
+    windows_or_buffers_changed = 31;
   return changed ? w : NULL;
 }