Deleting popup addresses in email

I've had Mountain Lion now for a week or two, and I'm having some problems with Contacts (used to be Address Book). I used to be able to click on a name in the Address Book and it would be added to an email I was composing. But now when I click on the name, a small window is opened showing that info. And it does not appear in the email address space. How do I do that now?

So I've been typing in the beginning of the name in the address space on the email, and the address pops up there. And usually another small window pops up showing a list of possibilities. I've twice now gotten into trouble choosing an out-of-date address. So my second question is how do I delete those old out-of-date addresses so that they don't pop up? They have, of course, been deleted from Contacts, but they continue to pop up.

To delete out of date or wrong addresses open mail and under the Window menu you will see "Previous Recipients" and you can delete any address you want.

Thank you, Pomeroy, for your astute revelation. It works beautifully.

Now if I could only figure out how to click on Contacts and have them appear in the email address box without having to type a couple of letters of the name.

Any suggestions there?