Cannot switch material on blueprint?

I have a “smelly” blueprint which is a duplicate of a smoke effect blueprint. I also made a duplicate material with new colors and effects to use on this new blueprint, but unreal won’t let me swap it out. What am I missing?

See attached screenshot:

Selecting the material from the dropdown, dragging the material from the content window, and selecting the material in the content window all does not work.

i feel like thats something that would have to be changed in the particle system itself. I just tried it out and i had the same issue as you when trying to change it in the details panel of the level viewport, but if i change it in the particle system itself it changes just fine.