Please don't store any instance of objects in a property in the default class you are exporting (line 7 `prefs.js`). that won't allow the garbage collector to do its job after window close: [EGO Review Guidelines: Destroy](https://gjs.guide/extensions/review-guidelines/review-guidelines.html#destroy-all-objects) You can make it local to `fillPreferencesWindow()` function and attach it to the window (`window._settings`) or you can clean up on: ```js window.connect('close-request', () => { // clean up here }); ``` If you need any help with your extension you can ask us on: - [GNOME Extensions Matrix Channel](https://matrix.to/#/#extensions:gnome.org) - IRC Bridge: irc://irc.gimpnet.org/shell-extensions