My app preferences are not updated

The app settings can be changed at any time in the app preferences page.

After you change any value, you must click 'Save' for the new settings to be applied:

At that moment the new settings are applied:

However, please note that the preferences are cached for a minute in your browser so, if you had already opened a page with the app widget in your browser, you have to refresh the cache to see the new settings applied. You can do that easily, for example, by pressing CTRL + F5 if you're on a Windows machine or SHIFT + 'Reload button' if you're on a Mac.

As a last resort, you can always clear your browser cache, but this should not be normally necessary.

Please check https://en.wikipedia.org/wiki/Wikipedia:Bypass_your_cache for shortcuts for all browsers and instructions on how to clear caches.