Restrictions prevent the edition of tables

In the attached DAN, if I add the restrictions that when CHD is absent then Eligible PCI is neither yes nor no, then I cannot edit the probability table for Eligible PCI.

(The reason for the restrictions is that PCI is a therapy for CHD (chronic heart disease). When there no CHD, it does not make sense to consider whether the patient is elegible for this therapy.)

I have found the same problem with other MPADs.