Conditional Transparency of Visuals

Hello,

I'm looking to create a single report page where I have a single slicer "Supervisor" , and a two visuals, only one of which is visible at a time. The visuals would be two stacked column charts on top of each other.

The default visible visual is a stacked column chart with x axis of Supervisor. When the supervisor slicer is used, I want the visual with x axis as supervisor to be invisible, and another visual (same data, but x axis of employee) to be visible.

I've got it close to working using link below instructions but when I go to select the "make transparent" measure in the fx menu of the background on the visual, I cannot select the measure becuase it is greyed out. Why would this measure be greyed out?

https://exceleratorbi.com.au/show-or-hide-a-power-bi-visual-based-on-selection/#:~:text=Click%20on%20Conditional%20formatting%2C%20Select,the%20%5BMake%20Transparent%5D%20measure.

In the screenshots below I have the charts next to each other, but once I get the transparency thing working they would be on top of each other, so that only one at a time can be viewed. Right chart is x-axis of supervisor, left chart is x-axis of employee.

And yes, I also realize this is similar in function to drilling down on a chart, but not quite the same. Any thoughts on how to accomplish this conditional transparency?