Grayed-out tiles? (haven't checked C:DDA updates for a while)

Straight to the point. I’ve just downloaded the recent 0.6.0 after not checking on Cataclysm for half a year. And so i found those gray tiles instead of colored ones, which go back to normal (colored) version when you step next to them. I think i make myself clear. So can someone explain this “gray-out” mechanics to me? And whether i could turn it off. (Although i might find it less annoying after being explained)

Pretty sure they’re lit tiles(colored). It seems to be what it is because windows always have a cone of lit tiles projecting into the house.

Well my first guess was the same. Nevertheless i liked my Cataclysm bright and fancy with all those colours. Hopefully someone suggests a way to disable this “dimming”

This right here.