These limitations apply to defining the bindings of independent dimensions for use in varying attributes:
The expression to define the binding for an independent dimension can be applied to either unique or duplicate outline deployments, but the expression should not be applied to both unique and duplicate members at the same time.
For a unique outline deployment, the result of the expression must match the caption binding of the class of the independent members.
For a duplicate outline deployment, the result of the expression must match the key binding of the class of the independent members.