screen reimplements its own internal permissions model That's exactly my point. This is neither categorically good nor bad. It doesn't reinvent permissions gra

screen reimplements its own internal permissions model That's exactly my point. This is neither categorically good nor bad. It doesn't reinvent permissions gratuitously, but, rather, as a way of increasing flexibility. It allows per-window permissions and fairly arbitrary permissionsetting, for any user, without resorting to groups (the membership of which a regular user does not control) or universal permissions.