Imagine that you have in your addressbook "Joel Smith <joel@smith.com>"

If I try to send an email to "joe@ximian.com" and I type "joe" it gets replaced
with "Joel Smith <joe@smit.com>".  But when I type the "@" sign the word should
be reverted to what I have typed so far, in this case "joe@", but instead it
leaves the casing incorrect as "Joe@"

This is a big problem because even when am typing the email address correctly,
if I do not pay attention, I will mail an address that will bounce (Joe@ does
not exist on the destination server).