1. When you use `setInterval()`, use `clearInterval()` instead of line 54 `serverStatusPanel.js`. 2. They won't get garbage collected after window close since you used `this` (line 14-16 prefs.js). Make the local inside that method. You can attach settings to the `window` in case you want to avoid garbage collecting before window close: https://gjs.guide/extensions/development/preferences.html#prefs-js

1. I don't understand. Line 54 of serverStatusPanel.js is GLib.source_remove(this.intervalID); What should it be? I don't have a clearInterval method. 2. Is it ok if extension.js has some global variables?

1. Missed that. Line 50 you used `this.setInterval()`. It's ok. you used `GLib.timeout_add()` inside that method. 2. Yes, only when you clean them up in disable. If you are asking that for prefs.js, you can use this to clean up in prefs.js: ```js window.connect('close-request', () => { // clean up here }); ```