Subject: bug#76084: 31.0.50; Dragging tab line does not resize windows, unlike header line or mode line

From: Jared Finder <[email-masked]>
Date: Wed, 05 Feb 2025 22:08:41 -0800

Dragging on empty space in the tab line does not resize windows.  This
is unlike the behavior when dragging on empty space in the mode line or
in the header line.

Additionally, hovering the mouse pointer over empty space on the the
header line, while it does resize the window, does not display the
"resize up down" icon.  This behiavor is differnt from when you hover
the mouse pointer over the empty space on the mode line.

(this is secondary bug filing requested in bug#75844)

   -- MJF

In GNU Emacs 31.0.50 (build 10, x86_64-pc-linux-gnu, GTK+ Version
  3.24.38, cairo version 1.16.0) of 2025-02-05 built on electric-egg
Repository revision: ea04dd8ca93d609c0ee475c4acf58a56dfc0f1f3
Repository branch: HEAD
Windowing system distributor 'Microsoft Corporation', version 
11.0.12010000
System Description: Debian GNU/Linux 12 (bookworm)

Configured features:
ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GPM GSETTINGS HARFBUZZ JPEG
LCMS2 LIBOTF LIBSELINUX LIBSYSTEMD LIBXML2 M17N_FLT MODULES NATIVE_COMP
NOTIFY INOTIFY PDUMPER PNG RSVG SECCOMP SOUND THREADS TIFF
TOOLKIT_SCROLL_BARS TREE_SITTER WEBP X11 XDBE XIM XINERAMA XINPUT2 XPM
XRANDR GTK3 ZLIB

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

Major mode: Info

Minor modes in effect:
   tab-line-mode: t
   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
   isearch-fold-quotes-mode: t
   global-font-lock-mode: t
   font-lock-mode: t
   blink-cursor-mode: t
   minibuffer-regexp-mode: t
   buffer-read-only: t
   line-number-mode: t
   indent-tabs-mode: t
   transient-mark-mode: t
   auto-composition-mode: t
   auto-encryption-mode: t
   auto-compression-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message mailcap yank-media puny dired
dired-loaddefs rfc822 mml mml-sec password-cache 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 tab-line icons info time-date cl-loaddefs
cl-lib compile text-property-search comint subr-x ansi-osc ansi-color
ring comp-run bytecomp byte-compile comp-common rx ruler-mode rmc
iso-transl tooltip cconv eldoc paren electric uniquify ediff-hook
vc-hooks lisp-float-type elisp-mode mwheel term/x-win x-win
term/common-win x-dnd touch-screen 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 theme-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 gtk x-toolkit xinput2 x multi-tty move-toolbar
make-network-process tty-child-frames native-compile emacs)

Memory information:
((conses 16 87290 9777) (symbols 48 7255 0) (strings 32 23302 2118)
  (string-bytes 1 771807) (vectors 16 13945)
  (vector-slots 8 170553 12886) (floats 8 33 40)
  (intervals 56 2441 157) (buffers 992 14))