Visibly select cell from a heatmap

Dash Python
1

I have a heatmap with categorical values in both x and y dimensions

A          
B          
C          
D          
  0 1 2 3 4

I can click on a cell and report back what that cell is or update another chart. I want to restyle the heatmap such that the opacity of everything else drops to 0.3 and have this update as I click new cells.

A           
B           
C      X    
D           
  0 1  2 3 4