A quick tip to highlight a selected item from a parameter. Here an example how it works. You create your parameter, in this case called ‘Choose a Sub-Category’ and then you create a calculated field that I am going to call ‘Highlight a Sub-Category’ as fallow.

You then drag the new calculated field on colour and once you pick your sub-category on your parameter the selected one will highlight in the graph.

Following a video to better explain the tip.