I had Thunderbird installed on my new MacBook Air last summer. Over the last month or so, when I start typing an address, instead of bringing up a menu of options that start with that letter, it brings up only the first one. So if that isn't the one I want, and I don't know the address by heart, I need to open the address book, find the address, go back into email and delete the address that Thunderbird put in the field. It doesn't always happen, but happens often enough. Any thoughts?