I didn't do it by clicking on a state. I did it by selecting a parameter value.
When you click on a state, that state will get highlighted. (And the rest get greyed out.) Selecting a parameter doesn't mess with highlighting.
Also, I couldn't figure a nice way to pump the selected state value into the calc machinery. Parameter selections are easier.
KNICKNACKS A.twbx 50.8 KB
Thanks Joe. While not exactly what i'm after, this heads me in the right direction.
The reason i'm asking for the control selection to be tied to clicks on the map is that users currently enjoy that functionality in an SAP application. I'm moving reports and dashboards to Tableau and it'll mean less explanation and training if the main functions work the same way.
I sincerely appreciate your help. I'll leave this open for another day or two to allow for other approaches but if none are forthcoming, i'll mark it as answered correctly.