emacs-27 17a1bb5: Fix redisplay when scrolling under redisplay-dont-pause

[Eli Zaretskii]

branch: emacs-27
commit 17a1bb5a032025d29413d5ad9316d3d001da3166
Author: Eli Zaretskii <address@hidden>
Commit: Eli Zaretskii <address@hidden>

    Fix redisplay when scrolling under redisplay-dont-pause
    
    * src/dispnew.c (update_window): Reset the window's
    'must_be_updated_p' flag if the window's update was completed
    without interruption.  This fixes redisplay glitches when
    'redisplay-dont-pause' is nil, at least on MS-Windows, because
    'expose_window' doesn't redraw the exposed rectangle when the
    window's 'must_be_updated_p' flag is set.
---
 src/dispnew.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/dispnew.c b/src/dispnew.c
index d79ae83..5b6fa51 100644
--- a/src/dispnew.c
+++ b/src/dispnew.c
@@ -3683,6 +3683,10 @@ update_window (struct window *w, bool force_p)
          W->output_cursor doesn't contain the cursor location.  */
       gui_update_window_end (w, !paused_p, mouse_face_overwritten_p);
 #endif
+      /* If the update wasn't interrupted, this window has been
+        completely updated.  */
+      if (!paused_p)
+       w->must_be_updated_p = false;
     }
   else
     paused_p = 1;