Email addresses stored in Collected Addresses not appearing as I fill in the To: field

I create a new email and type in the email address in the Write window (new email) To: field and send my email. I confirm that the email address I typed in appears in Collected Addresses: Name: John Smith Email: John@JohnSmith.com Then I create a new email. In the To: field, I start typing: J - nothing shows up. I type: o - So now Jo appears and still there is no attempt by Thunderbird to offer me the address John@JohnSmith.com. To send a 2nd email to John Smith, I must type the complete email address in the To: field, despite the fact that the complete email address is in Collected Addresses. Shouldn't Thunderbird attempt to auto-complete this email address as I type it?