After logging into one Stack Exchange site, when I visit another SE site, it says to me, welcome back - user - click here to refresh - web page.
Isn't it possible to refresh the page using code & without the user's interaction?
Because the auto-login process happens asynchronously. In other words, you may already be reading stuff, have already scrolled down, started typing, or whatnot, when the login process is completed. Automatically refreshing would be annoying in this case.
In one case, though, this will happen automatically (proving that it's not a technical problem): When you're on the login page, we take it as granted that you want to go back to whereever you clicked "log in" (e.g. on the chat site), so it's safe to automatically redirect you back.
This is a very valid question.
It's certainly possible to refresh the affected parts of the page automatically through ajax; asking the user to refresh themselves the page feels hacky..
It is a new feature, if you are already logged into one SE site, and you visit another SE site that you already have an account for, it will automatically log you in.
A user having logged into any SE-site will be automatically logged into every other SE-site on which they have an account
I think the 'click here' isn't needed. There is no need at all to show a notification bar. If SE is able to determine that the user is registered, they could 'just' put the username at the right spot at the top of the page.
The 'only' reason to refresh the page is the added functionality at the top of the page (StackExchange area with notifications, user area with hover) that nobody would miss really.
Edit Before clicking 'click here'.
The only difference I see is the 'Welcome' box on the right that was replaced by the 'Favorite Tag' and 'Ignored Tag' textbox.