How do I make a QDockWidget's size immutable? (`QtWidgets.QSizePolicy.Policy.Fixed` doesn't do anything.)

RokeJulianLockhart

Example

My code is undermentioned:

#!/usr/bin/env python3.12
PyQt6.QtWidgets.QDockWidget().setSizePolicy(
    PyQt6.QtWidgets.QSizePolicy.Policy.Fixed,
    PyQt6.QtWidgets.QSizePolicy.Policy.Fixed
)

The videos (youtube.com/watch?v=Rr5vkRM3eRw) linked in my comment at QTBUG-108675 demonstrate this. This also applies when they're docked, so I believe that that bug, which appears to be entirely dependent upon the compositor, WM, and display server, shouldn't be relevant.

Diagnosis

Per ru.stackoverflow.com/revisions/1606712/1, I tried setting solely one parameter, but that excepted.