This is about -> Edit Identity -> Cryptography settings.

Currently this shows the short keyid and all secret keys / all keys for encryption in the dialog.
In my opinion this would be better as a combo box that is prefiltered to only include keys where a UserID matches the configured mailbox.

Preselection should be similar to KeyForMailboxJob. E.g. the most recently generated valid key. (They should all be ultimately valid).

The Combo Box should also allow to select "generate key" which would start a KeyGeneration Job with default values and Name / Mailbox values taken from the identity dialog when the config is commited.

For compatibility with old users who may have configured keys that do not have a UID matching the Mailbox the old dialog could still be kept around and available as a fallback.