Version:            (using KDE 4.3.0)
OS:                Linux
Installed from:    Fedora RPMs

This has been a longstanding issue for me, going back to KDE3.  I don't really recall the disposition of the KDE3 feature request I had opened on this.  I think it fell stale for years and I finally closed it for lack of developer interest.  Thus, I'm reviving it here for KDE4.

Anyway, the problem remains that kmail provides no progress/status indicator when sending mail from an external application (e.g. digiKam).  Users have absolutely no clue as to the delivery status of the mail without taking the unnecessarily time consuming steps of opening kmail and checking outgoing/sent-mail folders.  This is particularly problematic for failed deliveries.   While it is possible to add a filter to play a sound upon sent mail success, this is hardly intuitive and still gives no visual indication.

Therefore, I recommend taking advantage of KDE4's new System Tray Notifications and Jobs component as a Notification "option" for kmail.  In this way, when configured, mail sent either from within kmail or externally (from digikam, for example) can provide the user with a useful progress/status indicator.  Perhaps it could/should be handled in a similar manner as file transfers are to/from konqueror.