Several other bugs exists that ask for enhanced S/Mime usability. Automatically select self's encryption and signing certificates by default, based on the email address, with the advanced option to explicitly select the desired certificates. This will restore the simplified behaviour that Communicator 4.x used. Allow the user to explicitly prevent other's from sending self encrypted messages, in a more understandable way - even when self owns a personal encryption certificate. Allow sending of encrypted messages, even if one does not own any certificate. Finer grained control when to send encrypted messages. Allow to configure how Mozilla Mail will behave, when sending encrypted is not possible. Either "ask whether to send anyway" (the more comfortable option used by Communicator 4.x) or "do not send, go back to compose window" (the safer, but less convenient option used by Mozilla 1.0 - 1.4.

This change requires replacing the current single S/Mime Mail Account Manager preference panel with three new panels. I'm attaching screenshots of an early implementation. The wording and layout might get improved, but I consider the order and distribution of elements already fixed for the work I'm planning to do.

This is an implementation of the new pref panels. It does not yet provide the new application behaviour.

In this patch, I will break the "lock S/Mime prefs" functionality, it is left to a future patch to fix it.

When the user composes a new messages, or the user replies to a mesage, the encryption/signing flags for this message will be set based on the default preferences. Whenever the uses switches the "from address" of the message to another account, a warning will be shown that encryption/signing flags might have changed.

As part of this message, signing newsgroup messages will also get enabled. Because we will have three separate preference panels, it will be easy to allow the specific configuration for news accounts. The pref panels "sending signed" and "receiving encrypted" will be available for newsgroup accounts. The pref panel "sending encrypted" will not be available for newsgroup accounts, because it does not make sense.

This prompt will be shown when sending the message using encryption is not possible, and the user has configured to be asked whether to send without encryption.

I think I should include another preference, to control whether to encrypt outgoing messages to self.