mh-refile-preserves-sequences-flag

mh-refile-preserves-sequences-flag is a variable defined in `mh-e.el'.
Its value is

t

Documentation:
*Non-nil means that sequences are preserved when messages are refiled.

If a message is in any sequence (except "Previous-Sequence:"
and "cur") when it is refiled, then it will still be in those
sequences in the destination folder. If this behavior is not
desired, then turn off this option.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 7.4 of the MH-E package that is part of Emacs 22.1.