State limitations of parameters in Tableau.

The main limitations are:

• A classic parameter holds one value at a time. There is no multi-select. - It is not data-aware. The list of allowable values is fixed when you create it, so new members appearing in the data do not show up automatically. - It does nothing on its own. Until a calculation, filter or reference line references it, changing it has no visible effect. - Values are typed. A parameter is a number, string, date or boolean, and cannot hold a mixture.

Dynamic parameters address the data-awareness problem by refreshing their list when the workbook opens or the data source refreshes. Single-value selection remains.

Where you genuinely need multi-select behaviour, a set or a filter is the right tool instead.