I've been working with UEngine and when going back to 3Dmax workflow I really miss this grouping boards for comenting a group of nodes in the material editor. I use it for organizing different parts of the blueprint functions or material animations or complex node functions. But I can find it useful when also organizing full materials on 3dmax.
For example, when working in archviz, I find it really usefull for example to differ from common materials, different areas... for example to gruop architecture materials, furniture materials, accessories materials, people, etc... all in the same viewport.
I sometimes use tabs, but at the end of the day I have lots of duplicated materials.
I attach a couple images of the idea.
