Impossible to add staged users to a group via /groups -> add user

[RGJ (Richard - Communiteq)]

Continuing the discussion from What happens when you add a staged user to a discourse group?:

@tobiaseigen

This does not yet seem to be properly developed functionality, since there is no way to add staged users via the /groups admin. It is possible to add a user via the user admin, however. When I look at the group members page, the user is listed there.

When you go to a group and press the “Add User” button, the user “cannot be found” through the subsequent dialog if the user is a staged user.

The other way around (going through the user and add the group) is there.

This is very confusing (and apparently like this since at least 4.5 years).