Cannot assign group on a library if not member, as Administrator

[perkooo]

On the administration page, we cannot assign a group to a library where we aren't member of.

Ex: I want to assign group People to the library Welcome, as my user isn't a member of the People group, I can't list it. I'm only able to list the group where I am, but I'm indeed logged as Administrator.

The option "ENABLE_SHARE_TO_ALL_GROUPS" fixes it but all simple users will have the possibility. Only the administrator should be able to do this with the option disabled.