Hi, we now have several locations that are capable of accessing the Yahoo Instant Messaging feature.
Yahoo Messenger itself, plus Yahoo Web Messenger, Yahoo All New Mail, My Yahoo, your Mobile phone, plus any other computer.etc etc.
Yahoo classifies all these programs as different 'locations or devices'
Yahoo currently do not allow you to have 2 open and active at the same time. If you have one open, and then move to another, one will close and you get a message telling you that you have been signed out. You CAN have Messenger and Mail open together as long as your status is set to "offline" in MAIL by using the drop-box next to your name and selecting 'Sign out of chat'. ( your chat contacts will remove themselves from the inbox until you make yourself 'available' again.)
You may think you are signed out of Messenger when this is not the case.
Hitting the 'X' when you close the Messenger page does not sign you out of Messenger it only closes that page - you have to Exit Messenger by right clicking the icon in the system tray.and selecting 'Exit' I suggest you make this setting. > (left click) Messenger > Preferences > General - check box "sign out of Messenger when I close the main window" > Apply > OK.
If the above does not apply and you suspect your account is being used by a hacker. When you get signed out, close all your Yahoo programs and type your name into this software. Hit "GO" and hopefully it will show you as "offline".
If not, contact Yahoo customer serviceshttp://detectinvisible.com/