The current design does not allow to edit the properties of those elements involved in Master-Slave connections. For example, when selecting an element belonging to a slave connection and trying to edit the material, this will not be possible.
Oppositely, this is enabled for macro connections, which can lead to confusions and time-consuming situations if changes are needed.
Example of such situation: Let's say that in a model there are tens of slave joints and also the model contains lots of macro connections and the material needs to be changed for all the plates in the model. Normally, if the model would have contained only macro connections, this would be a very simple change to make. However, this is not possible for slave models. The only workaround is to select connection by connection and break the relation with the master model.
Maybe there is a way to change this behavior.
Thank you!