`SettingsUtils` in prefs.js is not static anymore and; `settings` is local in line 89. So you don't need to dispose and null it out on `close-request`.

Thanks for the review. Alright, then I'll remove the window's close-request handler. Could you explain though why there is a difference? I must say that I lack any good understanding of what's going on behind the scenes with memory. What's the difference between: //1: function fillPreferencesWindow(window) { const settings = new SettingsUtils(); } --- //2. function fillPreferencesWindow(window) { const settings = SettingsUtils.getSettings(); } static class SettingsUtils { settings; static getSettings() { if (settings) { this.settings = ExtensionUtils.getSettings(); } return this.settings; } } --- Why in case 1 I do not need to nullify settings, and in the second case I would have to do it? Is it GJS-speciific thing? Btw, do I have to increment the version of my extension each time I upload a new version?

The static class in your example saving the `gsettings` in `settings` property. And that's like saving it in global but hiding it inside static class. and the version is auto increment here, It's good to match the ego version and repo version to avoid updates during development.