Duplicated layer doesn't keep shading properties of original layer

[momentmal]

Good: The layer i duplicate now keeps the set shading properties.

Bad: The duplicated layer doesn't keep the same shading properties, it kinda seems to go back to Meshlabs default setting or something:

If you e.g. incrementally reduce and clean your mesh you want to keep certain stages as layers, but there is no reason that duplicates of your layer should change its shading bevavior without specific user input.

Originally posted by @momentmal in https://github.com/cnr-isti-vclab/meshlab/issues/967#issuecomment-850476784