[Therion] Best approach for colouring elevations

[Tarquin Wilton-Jones]

> It could be that red is the first colour in the default map colour list


Nope, tested that. Software tester (and pseudo-developer) by trade ;)
It did a full paint of the entire cave using a map that I had not
selected. Made me think I had got my map structures wrong or selected
the wrong map.

> What if you add to the below sequence a lookup colour specification for bar at mycave that differs from foo's colour?

It takes the last one - whichever is specified last - that contains the
scrap. It does not take the one you select, unless that one happens to
be specified last.

Definitely feels like I have stepped off the edge of stable features
here. I will file a bug report.