[Therion] Rock border not creating boulders with smooth altitude shading

[Tarquin Wilton-Jones]

Hi folks,

I feel like I must have missed some email about this; surely someone
will have noticed before...

Boulders. They are made from line rock-border, which will create a
shaded boulder when closed.

Make an area of water. Create a line rock-border half-way into the
water, and half out of the water, but still in the passage. The boulder
is the same colour as the background. Translucent, sitting on top of the
water.

Set this:
color map-fg scrap

Still works the same.

Now set this:
color map-fg altitude

The boulder loses its colour, and is nothing more than a thick line, so
it stops looking like a boulder.

Set this, and the boulder returns to being a boulder:
smooth-shading off

Is this an intentional change, a known limitation, or a bug?

Cheers,

Tarquin