I request authorization for my app through OAuth as described here: https://developers.arcgis.com/documentation/core-concepts/security-and-authentication/browser-based-user-logins/
The sign in dialog appears with something like:
"App Name wants to access your ArcGIS Online account information".
But the sign in just gives access to the app. Confusingly it does not sign in the user which you can check by going in the same window to www.arcgis.com where you get sign in dialogue again.
Is there a way to actually sign in user into ArcGIS online? If I compare it with giving access by Google/Facebook etc, they give not only permission to app but also realy sign in the user.