Can't add local users to private or personnal circle

Hi,
I am using NC14.0.3 + circles 0.15.2.

When creating a private circle and selecting a local user to add to it, the dropdown menu disappears and I simply can not add that user.

Only way I found to add a user is asking him/her to request membership and validating the user.

Local users are provided by Active Directory.

Help !

Thierry

are you using custom theme ?

NC version 18 here, Cicles 0.19.3 and the problem is the same.
Either I can add one user to any type of circle or if I want to add second member to the circle, the previous member is being replaced.