You cannot edit calculated members or attribute dimensions, because their values do not reside in the database.
Dimensions composed of implied shares (or user-defined hierarchies) do not aggregate as conventional dimension hierarchies do. Therefore, implied shares may overwrite data edits made to parents of implied shares as the model is pivoted.
Example: Actual and Budget are implied shares of the parent Scenario. Scenario, however, is a categorical label, not an aggregation of Actual and Budget measures.