bug#56662: 29.0.50; Funny region highlights when highlight-nonselected-windows is t

[Visuwesh]

If two windows show a single buffer, then the region highlighting is
strange in the non-selected window.  It is not hard to reproduce,

    1. emacs -Q
    2. Visit a longish file.
    3. C-x 3 and scroll up in any of the window.
    4. M-: (setq highlight-nonselected-windows t) RET.
    5. Create an active region and compare the highlighting.

I'm attaching a screenshot to demonstrate the issue in case the
reproducer wasn't clear.

screenshot_202207201702.png
Description: PNG image

In GNU Emacs 29.0.50 (build 22, x86_64-pc-linux-gnu, X toolkit, Xaw scroll bars)
 of 2022-07-17 built on astatine
Repository revision: 5db4ec20fe4b428e15aa53208c9a9bfb037c0f30
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12101003
System Description: Debian GNU/Linux bookworm/sid

Configured using:
 'configure --with-sound=alsa --with-x-toolkit=lucid --with-json
 --without-xaw3d --without-gconf --without-libsystemd --without-cairo'

Configured features:
ACL DBUS FREETYPE GIF GLIB GMP GNUTLS GPM GSETTINGS HARFBUZZ JPEG JSON
LIBOTF LIBSELINUX LIBXML2 MODULES NOTIFY INOTIFY PDUMPER PNG RSVG
SECCOMP SOUND SQLITE3 THREADS TIFF TOOLKIT_SCROLL_BARS WEBP X11 XDBE XFT
XIM XINPUT2 XPM LUCID ZLIB

Important settings:
  value of $LC_MONETARY: ta_IN.UTF-8
  value of $LC_NUMERIC: ta_IN.UTF-8
  value of $LANG: en_GB.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Group

Minor modes in effect:
  shell-dirtrack-mode: t
  gnus-undo-mode: t
  recentf-mode: t
  eros-mode: t
  pdf-occur-global-minor-mode: t
  minibuffer-depth-indicate-mode: t
  repeat-mode: t
  display-time-mode: t
  display-battery-mode: t
  winner-mode: t
  delete-selection-mode: t
  straight-use-package-mode: t
  straight-package-neutering-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  show-paren-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tab-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  undelete-frame-mode: t
  buffer-read-only: t
  indent-tabs-mode: t
  transient-mark-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t

Load-path shadows:
/home/viz/lib/emacs/straight/build/faceup/faceup hides 
/home/viz/lib/ports/emacs/lisp/emacs-lisp/faceup

Features:
(shadow ecomplete emacsbug sh-script smie files-x ement-taxy svg-lib
dabbrev avy inspector misc expand-region text-mode-expansions
cc-mode-expansions the-org-mode-expansions er-basic-expansions
expand-region-core expand-region-custom cl-print shell-command+
cus-start smerge-mode log-edit add-log time-stamp executable mule-util
flyspell ispell org-pdftools pdf-annot facemenu org-noter org-element
avl-tree ob-C ob-shell shell ob-racket async ob-async cdlatex texmathp
ol-eww eww xdg url-queue mm-url ol-rmail ol-mhe ol-irc ol-info ol-gnus
nnselect ol-docview doc-view ol-bibtex ol-bbdb ol-w3m ol-doi
org-link-doi org-tempo tempo org-id org-refile ol-man org ob ob-tangle
ob-ref ob-lob ob-table ob-exp org-macro org-footnote org-src ob-comint
org-pcomplete pcomplete org-list org-faces org-entities org-version
ob-emacs-lisp ob-core ob-eval org-table oc-basic bibtex ol org-keys oc
org-compat org-macs org-loaddefs flow-fill mm-archive sort gnus-cite
mail-extr textsec uni-scripts idna-mapping ucs-normalize uni-confusable
textsec-check qp gnus-async gnus-bcklg gnus-ml network-stream nsm
nndraft nnmh nnfolder nnmaildir nnagent nnml nnnil gnus-agent gnus-srvr
gnus-score score-mode nnvirtual gnus-msg gnus-art mm-uu mml2015 mm-view
mml-smime smime gnutls dig nntp gnus-cache gnus-sum gnus-group gnus-undo
gnus-start gnus-dbus gnus-cloud nnimap nnmail mail-source utf7 netrc
nnoo parse-time iso8601 gnus-spec gnus-int gnus-range message sendmail
yank-media rfc822 mml mml-sec epa epg rfc6068 epg-config mm-decode
mm-bodies mm-encode mail-parse rfc2231 rfc2047 rfc2045 ietf-drums
mailabbrev gmm-utils mailheader gnus-win gnus nnheader gnus-util
mail-utils range mm-util mail-prsvr tabify man misearch multi-isearch
pulse etags fileloop generator imenu-xref xref bug-reference cc-mode
cc-fonts cc-guess cc-menus cc-cmds cc-styles cc-align cc-engine cc-vars
cc-defs shortdoc help-fns radix-tree reveal noutline outline
cursor-sensor recentf tree-widget vc-backup log-view pcvs-util vc diff
vc-git diff-mode vc-dispatcher display-line-numbers ement-room-list
ement ement-notify notifications ement-room face-remap shr pixel-fill
kinsoku url-file url-dired puny svg ement-lib ement-api ement-structs
plz color ement-macros taxy-magit-section magit-section taxy ewoc dns
server paredit edmacro kmacro eros time-date checkdoc lisp-mnt
flymake-proc flymake project warnings thingatpt wordel-autoloads
sokoban-autoloads ement-autoloads svg-lib-autoloads
taxy-magit-section-autoloads magit-section-autoloads dash-autoloads
taxy-autoloads plz-autoloads nov-autoloads esxml-autoloads kv-autoloads
transmission-autoloads lua-mode-autoloads nix-mode-autoloads
racket-mode-autoloads pos-tip-autoloads faceup-autoloads eros-autoloads
flymake-shellcheck-autoloads writegood-mode-autoloads
siege-mode-autoloads paredit-autoloads puni-autoloads
expand-region-autoloads filladapt-autoloads compose quail
scroll-other-window org-pdftools-autoloads org-noter-autoloads
change-env-autoloads math-delimiters-autoloads doct-autoloads
ob-async-autoloads async-autoloads emacs-ob-racket-autoloads
valign-autoloads cdlatex-autoloads auctex-autoloads tex-site pdf-occur
ibuf-ext ibuffer ibuffer-loaddefs tablist advice tablist-filter
semantic/wisent/comp semantic/wisent semantic/wisent/wisent
semantic/util-modes semantic/util semantic semantic/tag semantic/lex
semantic/fw mode-local cedet pdf-isearch let-alist pdf-misc imenu
pdf-tools package browse-url url url-proxy url-privacy url-expand
url-methods url-history url-cookie generate-lisp-file url-domsuf
url-util mailcap url-handlers url-parse auth-source eieio eieio-core
json map byte-opt url-vars compile comint ansi-color cus-edit edebug
debug backtrace find-func wid-edit pdf-view password-cache jka-compr
pdf-cache pdf-info tq pdf-util pdf-macs image-mode dired-x dired
dired-loaddefs exif pdf-tools-autoloads tablist-autoloads mb-depth
repeat visual-fill-autoloads olivetti-autoloads time format-spec battery
dbus filenotify xml dom disp-table lacarte-autoloads
shell-command-plus-autoloads winner ring delsel cus-load easy-mmode
avy-autoloads finder-inf vc-backup-autoloads compat-autoloads icalendar
diary-lib diary-loaddefs cal-menu calendar cal-loaddefs rx filecache
imenu-xref-autoloads derived chemtable-autoloads molar-mass-autoloads
saveplace-pdf-view saveplace bookmark text-property-search pp
saveplace-pdf-view-autoloads pcase inspector-autoloads xr-autoloads
straight-autoloads cl-seq info cl-extra help-mode straight subr-x
cl-macs gv cl-loaddefs cl-lib bytecomp byte-compile cconv vz-nh-theme
vz-options-theme rmc iso-transl tooltip eldoc paren electric uniquify
ediff-hook vc-hooks lisp-float-type elisp-mode mwheel term/x-win x-win
term/common-win x-dnd tool-bar dnd fontset image regexp-opt fringe
tabulated-list replace newcomment text-mode lisp-mode prog-mode register
page tab-bar menu-bar rfn-eshadow isearch easymenu timer select
scroll-bar mouse jit-lock font-lock syntax font-core term/tty-colors
frame minibuffer nadvice seq simple cl-generic indonesian philippine
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 emoji-zwj charscript
charprop case-table epa-hook jka-cmpr-hook help abbrev obarray oclosure
cl-preloaded button loaddefs faces cus-face macroexp files window
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget keymap hashtable-print-readable backquote threads dbusbind
inotify dynamic-setting system-font-setting font-render-setting
x-toolkit xinput2 x multi-tty make-network-process emacs)

Memory information:
((conses 16 947872 144120) (symbols ?0 41864 354) (strings 32 202927 26256) 
(string-bytes 1 8898786) (vectors 16 115827) (vector-slots 8 2229479 69518) 
(floats 8 2323 1272) (intervals ?8 44532 3002) (buffers 992 ?O))