How do I turn off Yahoo chat so it does not turn back on when I check mail?

I liked the old Yahoo so much better. I simply set my status to offline and that was that. Now Yahoo Messenger seems to keep turning back on when I check mail with the new Yahoo. I do not like to be disturbed. Ever. I already have enough distractions and don’t need a “friend” saying “Sup” or “hot chick” telling me her pix are at xxx. porn .com
I want to kill the thing. I have already spent 10 minutes looking at Yahoo’s FAQs and don’t see anything. Where is the info hidden? How do I turn it off?

Where the heck is the “Yahoo Mail Chat Status window” ?