bug#40278: 27.0.90; Flickering in Windows 10

[Nicolas Bertolo]

Sometimes the emacs windows will flicker badly. This often happens when

scrolling, just moving the cursor, or using clicking with the mouse on some part

of the buffer.

 

It can be reproduced with `emacs -Q` but it is much less pronounced than with my

custom configuration. I can post it if necessary.

 

The following steps can be useful to reproduce it:

1) Open a long C++ file.

2) Run (setq mouse-wheel-scroll-amount '(1)).

3) Mouse the mouse whell up and down fast.

4) Pay attention to the part of the screen that should show new content.

Sometimes it will flicker a few time before stabilizing.

 

 

In GNU Emacs 27.0.90 (build 1, x86_64-w64-mingw32)

of 2020-03-26 built on DESKTOP-0DKLDHI

Repository revision: e1f0e0892232221e6333b24788b97942c83ec738

Repository branch: emacs-27

Windowing system distributor 'Microsoft Corp.', version 10.0.18363

System Description: Microsoft Windows 10 Pro (v10.0.1909.18363.720)

 

Recent messages:

Sending...

Sending via mail...

<left-fringe> <mouse-1> is undefined

Save this mail sending choice? (y or n) n

Sending...done

Beginning of buffer [2 times]

C-x C-k C-x k is undefined

Quit

ESC ESC M-x is undefined

delete-backward-char: Text is read-only

 

Configured using:

'configure --prefix=/c/users/nicol/emacs/'

 

Configured features:

XPM JPEG TIFF GIF PNG RSVG SOUND DBUS NOTIFY W32NOTIFY ACL GNUTLS

LIBXML2 HARFBUZZ ZLIB TOOLKIT_SCROLL_BARS MODULES THREADS JSON PDUMPER

LCMS2 GMP

 

Important settings:

  value of $LANG: ENG

  locale-coding-system: cp1252

 

Major mode: C++//l

 

Minor modes in effect:

  tooltip-mode: t

  global-eldoc-mode: t

  electric-indent-mode: t

  mouse-wheel-mode: t

  tool-bar-mode: t

  menu-bar-mode: t

  file-name-shadow-mode: t

  global-font-lock-mode: t

  font-lock-mode: t

  blink-cursor-mode: t

  auto-composition-mode: t

  auto-encryption-mode: t

  auto-compression-mode: t

  line-number-mode: t

  transient-mark-mode: t

  abbrev-mode: t

 

Load-path shadows:

None found.

 

Features:

(kmacro mailalias mailclient browse-url vc-git diff-mode easy-mmode

cc-mode cc-fonts cc-guess cc-menus cc-cmds cc-styles cc-align cc-engine

cc-vars cc-defs help-mode pp shadow sort mail-extr emacsbug message rmc

puny dired dired-loaddefs format-spec rfc822 mml easymenu mml-sec

password-cache epa derived epg epg-config gnus-util rmail rmail-loaddefs

text-property-search seq byte-opt gv bytecomp byte-compile cconv

mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils

mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr

mail-utils time-date subr-x cl-loaddefs cl-lib tooltip eldoc electric

uniquify ediff-hook vc-hooks lisp-float-type mwheel dos-w32 ls-lisp

disp-table term/w32-win w32-win w32-vars term/common-win tool-bar dnd

fontset image regexp-opt fringe tabulated-list replace newcomment

text-mode elisp-mode lisp-mode prog-mode register page tab-bar menu-bar

rfn-eshadow isearch timer select scroll-bar mouse jit-lock font-lock

syntax facemenu font-core term/tty-colors frame minibuffer cl-generic

cham georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao

korean japanese eucjp-ms cp51932 hebrew greek romanian slovak czech

european ethiopic indian cyrillic chinese composite charscript charprop

case-table epa-hook jka-cmpr-hook help simple abbrev obarray

cl-preloaded nadvice loaddefs button faces cus-face macroexp files

text-properties overlay sha1 md5 base64 format env code-pages mule

custom widget hashtable-print-readable backquote threads w32notify

dbusbind w32 lcms2 multi-tty make-network-process emacs)

 

Memory information:

((conses 16 92013 15535)

(symbols 48 9465 0)

(strings 32 26206 2252)

(string-bytes 1 939680)

(vectors 16 14062)

(vector-slots 8 176785 28090)

(floats 8 33 182)

(intervals 56 3372 30)

(buffers 1000 17))