Oauth Dialogue Flow

The shorter version is shown for apps with legacy non-scoped permissions, where the app requests non-granular access.

The longer version is shown for apps with the new scoped permission, where the app can request access on a more granular level.

Dropbox will eventually migrate everything to the new scopes permission, in order to enable more granular permissions for all apps. You can find more information on the migration here. You can also find more information on using scopes in the OAuth Guide and authorization documentation.

You can't revert a scoped app to a legacy non-scoped permission, but you can reduce the size of that text by removing any scopes that your app doesn't need. You can either disable scopes for your app entirely, via the "Permissions" tab on the app's page on the App Console, or on the fly by requesting only the minimal set of needed scopes using the 'scope' parameter on /oauth2/authorize.