Hello mate, I replied to this in comments but I will re-explain here.

Unfortunately its just a limitation with coding. RimWorld vanilla coding does not give me an ability to have working layers with headgear, and it was too late to learn it. Changing it can cause problems with several saves and my Task Force 141 mod.

One of the prime ways to fix it for me was to enable Camera+ mod since for some reason it helps consistently allow balaclava under helmets.

At the moment I'm crossing my fingers on 1.5 fixing this issue, but as it stands its just bust for 1.4 and nobody is more frustrated about it than I am because I want the basic mechanic of masks under helmets, but the game won't give it to me.

Thank you bro i ask before i see here i hope they fix it 1.5 many good day to you and fan of your mod.

@Cat Kraken - Cheers mate, thanks

would it be possible to do that having it work only with rpg style inventory revamped
like if the mod detected rpg style inventory revamped it would allow such things?