Tkinter text widget scrolling uncontrollably under Wayland

Bug report

Bug description:

On Gnome with Wayland (current Debian testing), resizing a Tk root window to increase the height causes a contained Text widget to scroll uncontrollably to the bottom of the widget. If the widget is scrolled while this is happening, it keeps scrolling back to the bottom.

Resizing the window again by decreasing the height or changing the width, or clicking inside the text widget, usually stops the issue.

This happens with both the mouse scrollwheel and the tkinter scrollbar.

This doesn't happen on Gnome using X, or on Windows 10. I haven't tested on any other systems.

Minimal example:

from tkinter import *
from random import choice
from string import ascii_letters

root = Tk()
textwidget = Text(root)

for i in range(1000):
    textwidget.insert(END, f'{choice(ascii_letters)} ')

textwidget.pack(fill=BOTH, expand=True)
mainloop()

A screen-recording is attached using the above code and showing the issue, which occurs the third time the window is resized.

https://github.com/user-attachments/assets/964159fa-afdf-4885-ac74-d39ae003302c

I have no idea how to debug this in more depth, any suggestions welcomed.

CPython versions tested on:

3.13

Operating systems tested on:

Linux, Windows

Keine Datei oder kein Test im Repository ist angegeben. Führe zunächst das minimalen Tkinter-Beispiel unter GNOME mit Wayland aus und vergleiche anschließend das Größenändern und Scrollen unter X anhand der gemeldeten Reproduktionsschritte. Erledigt ist es, wenn das Größenändern das Text-Widget unter Wayland nicht mehr nach unten zwingt oder das Scrollen durch den Benutzer überschreibt.