The app should retain the selected default browser and search engine settings after closing and reopening the app. Specifically, if a user sets Gecko as the default browser through the "General Settings" tab or by using the "Switch" option in the "Extensions (Beta)" tab, these settings should persist as the default after restarting the app. Additionally, when a user selects a search engine and adds it to the drawer from the browser, the chosen engine should be retained as the default for that tab, even after closing and reopening the app.
