Dear Maintainer,

When running emacs in a KDE Plasma Wayland session, resizing the window causes
emacs to become unresponsive for several seconds. The window initially does not
change size and the window contents do not update in response to any input or
commands. After several seconds, the window is resized and the contents update
as normal, including any input issued while the window was unresponsive. The
application does respond normally to the close button on the title bar while in
this state. It also correctly processes input like `M-x kill-emacs`, suggesting
that the unresponsiveness is limited to rendering. The problem appears with
both horizontal and vertical resizing.

I can reliably reproduce this under Wayland. I have not been able to reproduce
it under X11. I have not seen this issue with other GTK apps like gimp or
darktable. Package versions that might be relevant are:

- emacs-gtk: 1:29.4+1-6
- linux-image-amd64: 6.12.12-1
- plasma-desktop: 4:6.3.0-1
- kwin-wayland: 4:6.3.0-2
- kwin-x11: 4:6.3.0-2
- nvidia-driver: 535.216.03-2

It turns out that the bug _will_ reproduce with emacs-pgtk if I run it
as `GDK_BACKEND=x11 emacs -Q`.

One detail I hadn't noticed before is that if I focus the minibuffer
with M-x while the window is unresponsive, the window title actually
does update correctly. I've observed this behavior with both emacs-gtk
and emacs-pgtk.

I was able to reproduce this bug under the nouveau graphics driver. As
with the proprietary nvidia driver, the problem manifested under
Wayland, but not X11.

I was _not_ able to reproduce this bug on a second system running Debian
testing, KDE Plasma, and Wayland, but which has an Intel integrated GPU.

I have also tried replacing emacs-gtk with the emacs-pgtk package. The
problem does _not_ manifest with emacs-pgtk under Wayland with the
proprietary driver.