Hide/Unhide Material palette

Salutations!

I have a small problem. Maybe a more experienced CS guru has an idea on how to tackle this issue?

I have been using Clip Studio now for quite some time and really prefer this to Photoshop. It has a really nice drawing feel! Recently I tried to dig deeper in modifying the workspace to my desire and how to integrate more sophisticated CS functions.

Today I was playing around with the Material Folder. Somehow during a sudden brainfart I clicked to "Hide" a certain "Material palette". Problems now are that I don't know which Material Palette and even if I knew, I don't see an option for unhiding/showing hidden materials.

I tried to find out at least which palette I removed, by double-checking with the online manual https://www.clip-studio.com/site/gd_en/csp/userguide/csp_userguide/590_material_plt/590_material_plt_variation.htm But I don't know for sure if it was a default one or rather a badly organised download/custom folder.

Any advise is appreciated. Have a gud day!