bug#45799: 28.0.50; Faces shrink unreadable on GUI when foreground/background color set in TUI

[Jean Louis <bugs@gnu.support>]

Problem:
========

When I use `emacsclient -c -nw' for `customize-faces', `default' and
unset foreground and background color, the GUI faces shrink to miniscule
sizes that I cannot even read any more.

How to reproduce:

1. emacs -Q

2. M-x server-start

3. open xterm

4. $ emacsclient -c -nw

5. within emacsclient in xterm: M-x customize-faces, then `default'

6. Move to foreground, background and unset it

7. save settings for the session

8. At this point the GUI shrinks its faces to something unreadable



In GNU Emacs 28.0.50 (build 4, x86_64-pc-linux-gnu, X toolkit, cairo version 1.14.8, Xaw3d scroll bars)
 of 2021-01-01 built on protected.rcdrun.com
Repository revision: 30a1d5da7a43d51a97cbe8d91add9a26dd99df90
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.11907000
System Description: Hyperbola GNU/Linux-libre

Configured using:
 'configure --prefix=/package/text/emacs --with-modules
 --with-x-toolkit=lucid
 PKG_CONFIG_PATH=/home/data1/protected/GNUstep/Library/Libraries/pkgconfig:/usr/lib/pkgconfig'

Configured features:
XAW3D XPM JPEG TIFF GIF PNG RSVG CAIRO SOUND GPM DBUS GSETTINGS GLIB
NOTIFY INOTIFY ACL GNUTLS LIBXML2 FREETYPE HARFBUZZ M17N_FLT LIBOTF ZLIB
TOOLKIT_SCROLL_BARS LUCID X11 XDBE XIM MODULES THREADS JSON PDUMPER
LCMS2

Important settings:
  value of $LC_ALL: en_US.UTF-8
  value of $LANG: de_DE.UTF-8
  value of $XMODIFIERS: @im=exwm-xim
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  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

Load-path shadows:
None found.

Features:
(shadow sort hashcash mail-extr emacsbug message rmc puny dired
dired-loaddefs rfc822 mml easymenu mml-sec epa derived epg epg-config
gnus-util rmail rmail-loaddefs auth-source cl-seq eieio eieio-core
cl-macs eieio-loaddefs password-cache json map text-property-search
time-date subr-x seq byte-opt gv bytecomp byte-compile cconv mm-decode
mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader
cl-loaddefs cl-lib sendmail rfc2047 rfc2045 ietf-drums mm-util
mail-prsvr mail-utils iso-transl tooltip eldoc electric uniquify
ediff-hook vc-hooks lisp-float-type 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 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 button
loaddefs faces cus-face macroexp files window text-properties overlay
sha1 md5 base64 format env code-pages mule custom widget
hashtable-print-readable backquote threads dbusbind inotify lcms2
dynamic-setting system-font-setting font-render-setting cairo x-toolkit
x multi-tty make-network-process emacs)

Memory information:
((conses 16 55676 7783)
 (symbols 48 7329 0)
 (strings 32 20390 2395)
 (string-bytes 1 650558)
 (vectors 16 13010)
 (vector-slots 8 225748 23461)
 (floats 8 26 39)
 (intervals 56 256 0)
 (buffers 984 12))

-- 
Thanks,
Jean Louis
⎔ λ 🄯 𝍄 𝌡 𝌚