The conventional meaning for ‘public’ refers to an external, often anonymous, community. In PageSeeder, ‘public’ means anyone NOT in the same group.
A helpful rule for PageSeeder solutions is that ‘roles filter functionality and groups filter content’. Or put another way, because every group member can see all content, permission models are expressed as constraints on the ‘public’ not the ‘members’.
To control whether non-members can see documents in the group use the
Public option on the Group Folders page.