I have many aliases that all point to a single POP3 account which I download my email from, and I would like to see these in the compose window in the FROM field. The only current way to do this is to create full non-working and POP3 accounts for ever single alias. This new option could be added as a new account type, or more simply just a work around option from the preferences.
Looks like a duplicate of bug 44863.
*** This bug has been marked as a duplicate of 44863 ***