Version:            (using KDE Devel)
Installed from:    Compiled sources

When the "Send Again" action is used, KMail does not clear and rebuild the message's old header information.  This is bad for the follwing reasons:

* Old "Received:" headers from a previous delivery confuse some MTAs into thinking mail is looping
* Old headers reveal too much information to the new recipient about where the message has been previously (IP addresses,  etc.)
Old "From:" information is used despite the composer interface showing the current identity's info (what shows in the UI does not match what is sent)
* Old application-specific header information (sieve, spam filters, etc.) may be confused into thinking that a new message has already been processed.
* MUA version information not set correctly if MUA has changed since message previously sent

In general, reusing old header info in a new message seems like a _very_ bad idea because of the possibility of confusing mail transport / handling applications and inadvertently leaking more message history than the user expects or probably wants.  These are real and serious problems.  I actually had a spam filter flag a resent message as spam because of this header weidness.  Also, I noticed that a message I sent using this feature included information about the previous history of the message.  Ouch.

I believe most people that use "Send Again" use it as I do as a simple message template facility to send the message message with minor changes to different people.  Fot that purpose this behavior is highly undesirable.

This evilness may have been added to close bug 43221.  The reporter of that bug actually asked for this behavior but gave no reason why this would be a good idea.  I cannot think of any reason myself and believe this should be fixed for increased interoperability and security.