Required mail & news headers

[Hanak David <dhanak@inf.bme.hu>]

Hi,

I discovered, that the contents of 'message-required-headers' are always
rendered *before* composing the message, as opposed to
'message-required-news-headers' and 'message-required-mail-headers', which
are affected by the value of 'message-generate-headers-first':

/----
| message-generate-headers-first's value is (references)
| 
| Documentation:
| *If non-nil, generate all required headers before composing.
| The variables `message-required-news-headers' and
| `message-required-mail-headers' specify which headers to generate.
| This can also be a list of headers that should be generated before
| composing.
\----

I don't want to see that X-Draft-From line, nor the From header, nor the
very long Face header whilst composing my message.  The latter can be
hidden by adding it both to ...mail-headers and ...news-headers instead of
adding it once to ...required-headers, but that doesn't seem nice.

'message-generate-headers' is readded to the headers-to-be-inserted list
(after being filtered by 'message-headers-to-generate'):

/----
| (defun message-generate-headers (headers)
|   "Prepare article HEADERS.
| Headers already prepared in the buffer are not modified."
|   (setq headers (append headers message-required-headers))  ; <---- !!!!
|   (save-restriction
|     (message-narrow-to-headers)
|     (let* ((Date (message-make-date))
| 	   (Message-ID (message-make-message-id))
\----

If I remove the line marked with !!!!, these headers are lost, because they
are not added later, as opposed to ...news-headers and ...mail-headers.

Unfortunately, these variables are not very well documented. :-(.  So, why
is this difference?  Is it on purpose?

David