keyshot 4 issue assigning color and material

[fungus99]

I've imported a SolidWorks file as and STEP file and have already applied all the surfaces with a different colour. However despite doing this and unlinking the chosen surfaces, dragging any colour or material will cause the entire part to chance as one.
What am I doing wrong?

[Will Gibbons]

Why not upload some screenshots from KeyShot?

I know SolidWorks allows you to apply materials at the surface, body, part and assembly level... so it depends on how you've applied your materials in SW and how you've moved your geometry into KeyShot.