[Therion] Splays appearing when not selected

[Tarquin Wilton-Jones]

> Tarquin, did you know, there is a "-walls off" option for scrap?

Very neat :)

I will certainly use that.

It does limit you though, to only being able to hardcode it into the
scrap. You could not prepare two different versions of the .lox by
selecting the relevant maps (plan and extended elevations at the same
time). You could prepare the two versions, but only by manually editing
the scraps in between.

For me, the existing solution is fine, but does seem oddly limited.