Unable to login and have both clients open for NA & PBE

Ever since the new client has been released i am unable to have both clients logged in like before the way everyone liked it as i asked everyone i know. Everyone says this bug is making their lifes harder at doing some testings on PBE and it takes forever to log over rather than like before where you just clicked on a window and you were already logged in and everything was perfect.

Fix this bug please where we can stay logged in on NA & PBE at the same time without having to sign out or close everything.