call <SID>NM_newFileBuffer(g:notmuch_compose_temp_file_dir, '%s.mail',
\ 'compose', lines)
setlocal bufhidden=hide
+ let b:nm_prev_bufnr = prev_bufnr
call <SID>NM_set_map('n', g:notmuch_compose_nmaps)
call <SID>NM_set_map('i', g:notmuch_compose_imaps)