[Kwpolska]

Here’s IDLE’s settings window on Windows 11: https://i.imgur.com/DnwviOr.png

Those combo boxes are definitely not native. The menus are also off (the menu items are shorter and they turn blue instead of gray when highlighted).

[aidenn0]

IDLE uses the pre-ttk widget set and is indeed ugly.

See https://tkdocs.com/tutorial/idle.html for a case-study involving IDLE (Search for "Another Example" to see the settings window). You should be able to tell from the windows and mac screenshots how old this article is.