We do NOT yet have the ability to define a label for an expression that is dynamic.
So when doing set analysis with dollar sign expansion, we cannot modify the column label so that it changes with the evaluation.
This is a significant problem as it does not give us many options for telling the users what each column is doing, if different from normal Qlik behavior.
Which object type is this in? Most of them have the expression builder for Labels so not sure which one that is. Can you use a master measure and set a dynamic label in there as a workaround?