Full email logins cause malformed initial email address

[jonwolf]

Using a login name such as john@doe.net (everyone who
is required to use their email as their IMAP login),
logging into the IMAP server mail.doe.net causes
RoundCube to initially configure the email address as
john@doe.net@mail.doe.net which causes problems when
sending mail. 

This is quickly remedied through the identity setting,
but can be confusing to a new user.

[nobody]

Logged In: NO 

irriating bug, its hard to explain to newbies too.

[nobody]

Logged In: NO 

I agree this is confusing.  There should be a switch in the 
config to specify your initial email address:
do nothing (login includes domain name), use server name, 
or add a specified domain.

[roundcube]

Logged In: YES 
user_id=1262041

Now checking if the user name contains an @ char. If not,
adding @hostname for identity e-mail address.