Most people who make use of 'do_findprevious' and 'do_findnext'
will not make use of 'do_search' (the default binding of M-W),
so for them it is superfluous to remember the state of the
Backwards toggle in the Search menu.  For the people that do
mix the usage of Alt+Up/Down with M-W, it means that M-W will
always search in the same direction as the last search.  It is
a small change in behavior.