gnus-summary-mail-other-window
gnus-summary-mail-other-window is an interactive autoloaded compiled Lisp function in `gnus-msg.el
'.
(gnus-summary-mail-other-window &optional ARG)
Start composing a mail in another window.
Use the posting of the current group by default.
If ARG, don't do that. If ARG is 1, prompt for group name to find the
posting style.