The November update of the WAB on AGOL has implemented the following feature:
The app state, including map extent and layer visibility, is now automatically saved when you close your browser.
The save occurs when you close the tab or refresh it. This is annoying when developing applications, and doing demonstrations, as you never get back to the initial state of the application just be reloading it. The only way around it I have found is to clear the local storage in the browser using the console or dev tools, which works as long as you are a) still on the site and b) have closed the app first.
I wouldl ike there to be a way to have an option to disable this, by user if possible, or in the app itself.