feedmail-nuke-buffer-after-queue

feedmail-nuke-buffer-after-queue is a variable defined in `feedmail.el'.
Its value is

nil

Documentation:
If non-nil, silently kill the buffer after a message is queued.
You might like that since a side-effect of queueing the message is
that its buffer name gets changed to the filename. That means that
the buffer won't be reused for the next message you compose. If you
are using VM for creating messages, you probably want to leave this
nil, since VM has its own options for managing the recycling of
message buffers.

You can customize this variable.