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

未指定 repository 中的檔案或測試。首先在使用 Wayland 的 GNOME 上執行最小 Tkinter 範例，然後按照回報的重現步驟比較 X 下的調整大小和捲動行為。完成的標準是：在 Wayland 上，調整大小不再強制 Text widget 捲動到底部，也不再覆寫使用者的捲動操作。