> For the moment I've gone with my simpler separation of 'keys which have > been set' and 'keys which have not'. I've yet to write the docs, which > may reveal issues, but my thinking currently is that key filtering is a > way to assign only some keys in particular contexts, but that elsewhere > either the 'balance' will be set or all keys will be set Fair enough. I'm more than happy with the last version! :) How would you feel about also adding Fitler/Groups versions of \ProcessKeysOptions and \ProcessKeysPackageOptions to l3keys2e? There's a typo in row 291 of l3keys.dtx (should be '\enquote' in place of '\enquoe’). Beyond that, I just want to thank you for all your patience and effort put in! Best, Jura