On Tue, 31 Jan 2012 17:03:55 +0200, Jani Nikula <jani@nikula.org> wrote:
> 'a' = Archive current message, then move to next message, or show next
> thread from search if at the last message in thread.
> 
> 'A' = Archive each message in thread, then show next thread from
> search.
> 
> 'x' = Archive current message, then move to next message, or exit back
> to search results if at the last message in thread.
> 
> 'X' = Archive each message in thread, then exit back to search
> results.

This seems consistent to me and would be an improvement.