bug#54196: 29.0.50; flat-button face box style does not work as expected

[David Ponce <da_vid@orange.fr>]

Hello,

I noticed that the :box :style flat-button is not working as expected:
the line around the text seems to be there, but not visible.

Just evaluate the below code in the scratch buffer will show the
problem:

(insert
  (propertize "This buffer is for text"
	     'font-lock-face
	     '( :box ( :line-width (4 . 4)
		       :color "dark grey"
		       :style pressed-button)))
  "\n"
  (propertize "This buffer is for text"
	     'font-lock-face
	     '( :box ( :line-width (4 . 4)
		       :color "dark grey"
		       :style released-button)))
  "\n"
  (propertize "This buffer is for text"
	     'font-lock-face
	     '( :box ( :line-width (4 . 4)
		       :color "dark grey"
		       :style flat-button)))
  "\n"
  )

Thanks


In GNU Emacs 29.0.50 (build 2, x86_64-pc-linux-gnu, GTK+ Version 3.24.31, cairo version 1.17.4)
  of 2022-02-28 built on kilauea
Repository revision: 66899628f8a8c79ca8dfe32094f11a8320630fae
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12014000
System Description: Fedora Linux 35 (KDE Plasma)

Configured using:
  'configure --prefix=/home/dponce --with-cairo --without-sqlite3
  PKG_CONFIG_PATH=/usr/local/lib/pkgconfig:/usr/lib/pkgconfig'

Configured features:
ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GSETTINGS HARFBUZZ JPEG JSON
LCMS2 LIBOTF LIBSELINUX LIBSYSTEMD LIBXML2 M17N_FLT MODULES NOTIFY
INOTIFY PDUMPER PNG RSVG SECCOMP SOUND THREADS TIFF TOOLKIT_SCROLL_BARS
WEBP X11 XDBE XIM XPM GTK3 ZLIB

Important settings:
   value of $LC_TIME: fr_FR.utf8
   value of $LANG: fr_FR.UTF-8
   locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
   tooltip-mode: t
   global-eldoc-mode: t
   eldoc-mode: t
   show-paren-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
   indent-tabs-mode: t
   transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message yank-media rmc puny rfc822 mml
mml-sec epa derived epg rfc6068 epg-config gnus-util mm-decode mm-bodies
mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail
rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils mule-util info
help-fns radix-tree cl-print debug backtrace help-mode find-func
cus-theme eieio-custom xwidget url-handlers image-mode dired
dired-loaddefs exif browse-url url url-proxy url-privacy url-expand
url-methods url-history url-cookie url-domsuf url-util url-parse
auth-source cl-seq eieio eieio-core cl-macs eieio-loaddefs
password-cache json map url-vars mailcap format-spec bookmark
text-property-search wid-browse tree-widget seq gv byte-opt bytecomp
byte-compile cconv crm thingatpt cus-edit pp cus-start cus-load wid-edit
time-date subr-x cl-loaddefs cl-lib 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 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 emoji-zwj charscript charprop case-table
epa-hook jka-cmpr-hook help simple abbrev obarray cl-preloaded nadvice
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 lcms2
dynamic-setting system-font-setting font-render-setting cairo
move-toolbar gtk x-toolkit x multi-tty make-network-process emacs)

Memory information:
((conses 16 124700 10967)
  (symbols 48 10190 1)
  (strings 32 32692 1842)
  (string-bytes 1 927675)
  (vectors 16 18068)
  (vector-slots 8 233951 17277)
  (floats 8 53 116)
  (intervals 56 5791 0)
  (buffers 992 14))