Group membership feeds per-monitor access through Groups_Permissions, but
the classic group actions and the Groups API checked only the global
Groups permission. A Groups editor could add a monitor they are denied to
a group they have access through, or remove it from, or delete, the group
that denies it.
Add Group::canEditMembership() and require it, in both the classic UI and
the API, for every monitor added to or removed from a group, for all of a
group's monitors when it is re-parented, and for all of them when it is
deleted. The API also pins the record id and omits monitors the user may
not view from the groups it lists.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
