bug#58164: 28.1; keybinding C-z to suspend-frame in fvwm windowmanager seems to get lost after first use.

[Jos de Kloe]

After migrating from emacs 27.2 to emacs 28-1 (default versions in 
Fedora 35 and Fedora 36) I observe a strange behavior for the C-z 
key-binding.
It only occurs if I use fvwm as windowmanager (which is still X11 
based), and is absent if I use xfce in stead.

For emacs 27-2 all works as intended and C-z will let the emacs window 
iconify. And double clicking the iconified emacs will raise it again. No 
problems here.

But for emacs 28-1 the C-z command works only once. If I raise emacs and 
try again to issue C-z it does not iconify, but looses focus in stead.
Also after regaining focus by moving the mouse out and back in to the 
emacs window, C-z does not return to its intended behavior.

I tested with the standard Fedora versions:
   emacs-1:27.2-9.fc35.x86_64
   emacs-1:28.1-2.fc36.x86_64
on a Fedora 36 workstation installation.

I also tested this by downloading the emacs sources for versions 27-2 
and 28-1 and compiling it myself, and the situation does not change. The 
bug is present in version 28-1 and absent in version 27.2.
So there is no relation to the Fedora packaging process. It really seems 
to be a bug inside emacs itself.




In GNU Emacs 28.1 (build 1, x86_64-redhat-linux-gnu, GTK+ Version 
3.24.34, cairo version 1.17.6)
 of 2022-07-15 built on buildhw-x86-02.iad2.fedoraproject.org
Windowing system distributor 'The X.Org Foundation', version 11.0.12014000
System Description: Fedora Linux 36 (Workstation Edition)

Configured using:
 'configure --build=x86_64-redhat-linux-gnu
 --host=x86_64-redhat-linux-gnu --program-prefix=
 --disable-dependency-tracking --prefix=/usr --exec-prefix=/usr
 --bindir=/usr/bin --sbindir=/usr/sbin --sysconfdir=/etc
 --datadir=/usr/share --includedir=/usr/include --libdir=/usr/lib64
 --libexecdir=/usr/libexec --localstatedir=/var
 --sharedstatedir=/var/lib --mandir=/usr/share/man
 --infodir=/usr/share/info --with-dbus --with-gif --with-jpeg --with-png
 --with-rsvg --with-tiff --with-xpm --with-x-toolkit=gtk3 --with-gpm=no
 --with-xwidgets --with-modules --with-harfbuzz --with-cairo --with-json
 --with-native-compilation build_alias=x86_64-redhat-linux-gnu
 host_alias=x86_64-redhat-linux-gnu CC=gcc 'CFLAGS=-DMAIL_USE_LOCKF -O2
 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches
 -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2
 -Wp,-D_GLIBCXX_ASSERTIONS
 -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong
 -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic
 -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection'
 LDFLAGS=-Wl,-z,relro
 PKG_CONFIG_PATH=:/usr/lib64/pkgconfig:/usr/share/pkgconfig'

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

Important settings:
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: @im=none
  locale-coding-system: utf-8-unix

Major mode: Text

Minor modes in effect:
  tooltip-mode: t
  global-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 rmc puny dired dired-loaddefs
rfc822 mml mml-sec epa derived epg rfc6068 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 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 hashtable-print-readable backquote threads
xwidget-internal dbusbind inotify dynamic-setting system-font-setting
font-render-setting cairo move-toolbar gtk x-toolkit x multi-tty
make-network-process native-compile emacs)

Memory information:
((conses 16 68513 5974)
 (symbols 48 6648 2)
 (strings 32 19711 2609)
 (string-bytes 1 675049)
 (vectors 16 14175)
 (vector-slots 8 300265 11315)
 (floats 8 22 33)
 (intervals 56 272 0)
 (buffers 992 12))

--
*******************************************************
  dr. J. de Kloe
  jos.de.kloe@knmi.nl  kloedej@knmi.nl
*******************************************************