How do you make the body group changer do anythign?

[CommanderMayhem]

I've been fooling around forever and I accidentally removed an engineer helmet, but I didn't know what the fuck I did, how do I replicate this, or do some thing again? I don't understand the bodygroup changer.

[HyperTails]

I'd like to know this as well.

[Mega Tuna]

I dont think its up to specs with the engineer update, as i can remove the helmet and put it on, but no gunslinger. Its the top scrollbar in the context menu