learning specialization how can we define activities as required ?

Summary

learning specialization how can we define activities as required ?

Content

Hello,

In learning specialization it looks like the specialization itself can be defined as required ,
but then all the activities related to the specializations are defined as voluntary.

How can we define some of the offering/activities under specializations - to be required and some voluntary ?

Please see screenshots attached,

Thanks 
Revital