Object color change in 2.80

Newbie status ! Using 2.80 I have appended two (linked) objects into a new scene and separated them.
I have removed their colors and created the new colors.
I can open either of them in the shader window where they open with the correct colors showing in the preview panel on the right
BUT, I cannot get the objects to show in the new colors.

When I did this before with 2 similar objects they both showed the new color immediately so what am I doing wrong this time?
Any suggestions/advice would be really appreciated. Thanks

Although I have not had any replies I am answering this myself (for the benefit of other newbies) because I have it working now.
I think I was confusing blender by not having sorted out the image texture libraries properly.
By selecting the object, then deleting the existing material slots and creating the new materials/slots I wanted, the system started to work and is now fully functional.