[Bug]: What is association plot doing?

### What happened?

In `tm_g_association` one can select multiple associated variables to compare with reference variable. When multiple **Associated variables** are  selected nothing changes...


<img width="1207" height="830" alt="Image" src="https://github.com/user-attachments/assets/7ffc09fa-0076-4a78-af3d-170cac99b245" />

source: https://rinpharma.shinyapps.io/nest_exploratory_stable/

 
