In Mail I have two different gmail accounts that I use for different purposes. The problem is that sometimes I send a mail with an account, and then the sent email appears in both the accounts boxes. I don't know what happens, it's like if Mail sends the emails using both accounts. For example I write an email:
And I expect that the email is sent from my firstname.lastname@example.org account, but if I go to check the sent emails, the message appears also in the other account.