Well, I think in this case, the shadow race isn't just the darkness on a
surface caused by something solid blocking the light from shining there, so
shadows shouldn't DEPEND on lighting conditions as such, but I do think there
is a valid point that you shouldn't be able to see a shadow when it's dark, so
maybe they deserve something along the lines of (if maybe slightly different
to keep flavour among races) drow's hiding in darkness thing. Not likely to
ever happen I guess since it would probably be too out of tune or something,
but still, just a thought