If you create an email from a record e.g. invoice, then send the mail to the queue by ticking Sent, there are two links with identical text in the link manager of the invoice. For example:
Invoice 12345
Invoice 12345
This is confusing as it's not clear that one links to the mail record and one links to the mail queue record, nor that either link relates to mail at all. In older versions, the links appeared like this, which is much better:
Mail: Invoice 12345