Emacs-desktop insists on having 13-pixel scrollbars at startup

[PierGianLuca <luca@magnaspesmeretrix.org>]

Hi everyone.

Setup:

– Emacs 29.3 compiled on Ubuntu 20.04 from tarball, with options

./configure --with-native-compilation --with-json --enable-link-time-optimization --with-x-toolkit=gtk --with-xwidgets --without-toolkit-scroll-bars

– KDE Plasma desktop

– *No* window rules set for Emacs on KDE desktop

– *No* frame-geometry rules given to Emacs at startup in the emacs.desktop and emacsclient.desktop files

– early-init.el is empty

– default-frame-alist set, via customize, to:

  '(default-frame-alist
    '((horizontal-scroll-bars)
      (width . 87)
      (height . 80)
      (left . 1257)
      (top . 0)))


With this setup, Emacs starts with vertical scrollbars that are 13 pixels wide. If I create new frames with C-x 5 2 ('make-frame-command'), they also have 13-pixel-wide scrollbars.


I would like to change the scroll-bar width, adding 6 pixels. So I modify:

– early-init.el:

(setq-default scroll-bar-width 19)
(add-to-list 'initial-frame-alist '(scroll-bar-width . 19))


– default-frame-alist set, via customize, to:

  '(default-frame-alist
    '((horizontal-scroll-bars)
      (scroll-bar-width . 19)
      (width . 87)
      (height . 80)
      (left . 1257)
      (top . 0)))


What happens is that when I start Emacs, the *first* frames that appear have 13-pixels scrollbars. But any new frames that I create with 'make-frame-command' do have the requested 19-pixell scrollbars.


I discovered that this happens when Emacs-desktop is active. Emacs-desktop remembers the final frame geometry of all opened frames from one session to the next. Except that it always uses 13-pixel scrollbars for the restored frames when starting a new session. Frames created afterwards do have the correct scrollbar width – but they also will be reset to 13 pixels if Emacs is closed and started again.


If Emacs-desktop is disabled, Emacs starts with a frame having the required scrollbar width.


Is this a bug in Emacs Desktop, or am I missing or misunderstanding how it should work? I'm happy to share any other information you need.

Cheers!
Luca