Description of Problem:
When you compose a new email you can select the 
account the should appear in the from: field. It 
would be cool if you could edit this field.
I was using "The Bat!" until I switched to 
Evolution and this was a very handy feautre of 
"The Bat!". Sometimes you want to use a different 
Name/Email than configured in the account. E.g. I 
subscribe to mailing lists using 
listname@mydomain.tld but my regular account is 
fobar@mydomain.tld. Since my mail server delivers 
everything to fobar@mydomain.tld I receive the 
mails from the lists I'm subscribed to.
If I want to sent an email to this lists (or 
unsubscribe) I have to change my account for my 
emails to be accepted by the list(server).