selecting uid in a key

[Joseph]

I've generated a key pair and added a user ID (another email) to the
same key.

However, when I go to sign a file I'm only presented with the second
user ID when signing a file.

pub   
sub   
(1)  First Name (ID)(created when generating original key)
(2). Send Name (ID) (was added later)

What do I do so when I sign a file my "First Name (ID)" appear as a
default name.

Does it have something to do with that small "dot" after the second
number "(2)."

Thanks,
Joseph