Material display with skylight on seems wrong

Enabling the Rhino Skylight visibly darkens all grasshopper display, and especially messes with the appearance of custom shaders using the custom preview component. Without skylight on, the diffuse color is favored (as would be expected) - with skylight on, it appears to be the emissive color of the material that dictates its appearance in the Rhino viewport. This means there's no variation in shading on the surfaces of the objects.