A good addition to Valentina would be to enable the user to define material colors in the preferences menu.
The use case would be if a user has a production ready pattern, to easily, and visually, see what pieces have what material, while not actually viewing the piece label from up close. While one user may know from the top of their heads which piece has which material, while another user may not. Imagine a company where two or more people work on a single file, the newer user will quickly see which piece is which material
User should be able to define their own colors - both of the standard materials included, like fabric-lining-etc, as well as the user defined materials recently added to valentina.