@Dr-Sassi Thanks. I got it. And now I understand what you mean. It would be a good idea to have layer support for instances.
You can remove the file now.

@Dr-Sassi thanks. I wil build it up in another way.
And sent a request to Support to add layer support for instances.

Where can I download the C.O.F.F.E.E. Filter plugin?

@Dr-Sassi Hi. Here is a test file to explain.
I have to fill a shop with dozens of shelves and it would be nice to toggle the products on and off.
Try to toggle on and off the "bottles and stuff" layer and see what happens.

https://www.dropbox.com/scl/fi/nr4rodcltc5euy4mtxvb4/test.c4d?rlkey=ln3cyj09j54oob7qs0qubayn6&dl=0

How can I use layers with instances.
I have a Group which consists of several objects on several layers.
When I switch of layer 1 of object 1 the object becomes invisible.
But when I make an instance of this Group, layer 1 becomes visible again.
How can I solve this?

@Dr-Sassi

I found out I had the N~Q (Viewport, Options> Options> Materials) turned on in the render viewport and turned off in the current work viewport.
So problem was all on my side.

@Dr-Sassi Thanks. That Overwrite Material effect is a great option.
For now I just made a screen recording, another option

How can I render my viewport without textures?
I am testing a quick animation with the Viewport Renderer but all textures are visible.

@Dr-Sassi Done. Shared the Idea

Is it possible to set the default material projection to Cubic in stead of UVW Mapping and the Projection Display to Grid in stead of Simple when dropping materials to a polygon or primitive?