Hi Patrick,

I don't think this is possible with parameters. This could be done using filters.

~Tushar

An important distinction.  You said: "The Category Parameter draws its values from the same dimension."

That's not quite right.  When you created it, that's what happened.  But once it's created, the values in the parameter have no connection whatsoever to the original source.  The parameter is just a standalone list of values.

Tableau does not natively offer a way to refresh the values in a parameter automatically.  There are Extensions which can do that, but I'm not aware of anything that would restrict the values in the parameter to the results of a filter selection.

Good morning

I understand what you are trying to do but as noted above that is not the way parameters work - they are static single values selected by the user  but you can accomplish the goal ---  use a single parameter , a set and and then filter on the set

create the parameter

then create the set

then place the set on the filter shelf and select show members in set

and you get a filter that no longe list the parameter selected

Jim

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so you understand that tableau does not support  do what you wanted?