bug#73244: Emacs29.3 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.41

[Eli Zaretskii <eliz@gnu.org>]

> From: Po Lu <luangruo@yahoo.com>
> Cc: "John Hurst" <ajh@ajhurst.org>,  73244@debbugs.gnu.org
> Date: Sat, 21 Sep 2024 17:58:00 +0800
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> Date: Sat, 14 Sep 2024 12:42:50 +1000
> >> From: "John Hurst" <ajh@ajhurst.org>
> >> 
> >> The bug I have, since upgrading to Ubuntu 24.04 and install emacs29 is that the initial frame has width x height of 20 x 9, even though I have a .Xresources file containing
> >>    Emacs*geometry: 100x40+1900+0
> >> end a default-frame-alist of
> >>   Value:
> >>   ((font . "Monospace-10")
> >>    (height . 42)
> >>    (width . 90)
> >>    (tool-bar-lines . 0)
> >>    (menu-bar-lines . 1)
> >>    (top . 0)
> >>    (left . 1200))
> >>   Original value was nil
> >> set up by my .emacs file.
> >> 
> >> Using either the pull-down File->New Frame, or C-x 5 2, both generate new frames of the 20 x 9 size.
> >> 
> >> I can send the .emacs file if needed, but note that "emacs -D' also gives the same default size of 20 x 9, so I don't think it is a problem with my .emacs file - which did work OK under Ubuntu 22.04 and emacs28.
> >
> > Po Lu, any comments or suggestions?
> 
> >From what I've heard, the culprit is rather the upgrade to Ubuntu 24.04
> than to Emacs 29, and the problem will disappear if Emacs is configured
> with another toolkit than GTK.

Does it mean that GTK which comes with Ubuntu 24.04 is unusable with
Emacs?  What exactly in GTK causes this?