It makes a big difference for signatures (both encrypted and unencrypted) whether an email is in PGP/Inline or PGP/MIME format. The reason is that you can delete attachments from a PGP/Inline email without breaking the signatures. For experts it's just a short look at the message source code but that's obviously not an option for the general public. The message "signed by foo@bar" should be replaced by e.g. "PGP/Inline message signed by foo@bar". It would be nice to show a short explanation if the problem to the user if he clicks on "PGP/Inline" or "PGP/MIME". Reproducible: Always