I just noticed that editing a WordPress page with MarsEdit forces that page to become a "public" page. WP has the concept of private pages documented at http://codex.wordpress.org/Content_Visibility
and a private page can be treated in various ways by a WP theme. Usually themes will prevent these pages from showing up in navigation bars and menus. When MarsEdit saves a page, this "private" flag is lost and the page lands in the navigation. Not good.
Also, this makes me wonder what other sort of hidden metadata is being eliminated or reset when I edit a page with WP. This may be a WP problem for all I know. Maybe WP does not share these settings in the first place? In any case, it is pretty much a showstopper for editing private pages.
Does anyone have a solution? Is the private flag the equivalent of a "server custom field name" for example? If so, maybe I can just define it in MarsEdit?