AT&T Mail Account Login
When I go to https://currently.att.yahoo.com/ and select Sign In, it automatically signs me into the last account I was logged into. I have 4 different accounts and it won't let me change the one I sign into. Sometimes I don't even get the chance to tell it which account I want to sign into. Sometimes it gives me the account and password dialog window, but no matter what I enter, it still logs me into the last account I was logged into. How do I turn off this annoyingly stupid feature?