Issue with Data Security Policy

Hi All, I am trying to create custom role for Custom Screens. In the seeded role 'Custom Objects Administration' there are Data Security Policies with Data Set condition 'Functional Grant' but this option does not load in Data Set LOV when creating new Data Security Policy. If anyone faced this issue please suggest how to have 'Functional Grant' option load in the LOV of Data Set when creating new Data Security Policy. As of now only three values are shown in the LOV- All Values, Select by Key, Select by Instance Set.