Hi Pilou, thanks for posting the idea here!

It is an interesting idea and looks like it would be easy to use which is good!

But one big problem would be the limitation of only 8 slots... I don't think it will be too unusual for people to want to have many more categories than that on complex models.

To handle a larger number of categories, I think that it will be necessary for the list of "layer"s (or tags, categories, whatever it will be called) to be in a vertically arranged list, probably in some kind of additional side pane on the right-hand side of the window that can be turned on or off.

I think it would be possible to add some kind of quick access toolbar like this as some additional option later on, but there probably needs to be a more general purpose and less limited mechanism set up first.

- Michael