Table pop-up - settings service variable

I remember that a while back, another variation of the setting service variable was introduced specifically for table pop-up windows. It involved having “$$settings” at the end of the variable (i.e., $<<INST.DIM.HIER$$settings>>) and was designed to account for situations where you wanted the settings service to be independent in the pop-up window.

For example, perhaps we are passing a C-level Cost Center element from the main screen to the pop-up window filter (defined as the descendants of that setting service variable). If we use the normal $<<INST.DIM.HIER>> syntax as the variable, each time a user selects another element from dropdown, the settings service now only shows those descendants in the filter. The $$settings suffix was supposed to account for such situation by “locking” the settings service variable passed thru to the pop-up so subsequent selections on the pop-up filter does have this unintended recursive drilling effect.

I’m having some trouble finding the documentation of the syntax for this. Tried $<<INST.DIM.HIER$$settings>> but it returns an MDX error now (not sure if my syntax is correct). Does anyone know if this variation of the settings service variable still valid? Thanks!