1. Extensions cannot use `run_dispose()` (line 36 `prefs.js`): [EGO Review Guidelines: run_dispose](https://gjs.guide/extensions/review-guidelines/review-guidelines.html#extensions-should-not-force-dispose-a-gobject) 2. Don't hold any instance of objects in the class that init returns in prefs if you don't want to clean up on window close. for example, line 29, 32, ... `prefs.js`. I recommend using `fillpreferenceswindow()` to have access to `window`. That way, you can easily catch window close request and clean up: [GNOME Shell 42 Port Guide: fillpreferenceswindow](https://gjs.guide/extensions/upgrading/gnome-shell-42.html#fillpreferenceswindow) ```js window.connect('close-request', () => { // clean up here }); ``` 3. Use `console.*` instead of `log()`: [Port Guide 45: Logging](https://gjs.guide/extensions/upgrading/gnome-shell-45.html#logging)