Yes with these two mappings mentioned earlier in this thread, all lines are indented after o<Enter><Enter><Enter>::inoremap <Enter> <Enter><space><bs> :nnoremap o o<space><bs>
Got it! With these two mappings, it works correctly. Apparently on my system (vim version 6.4, modified by Gentoo) ':imap o o<space><bs>' does not work as expected. Thanks! Laurent Birtz
