Thanks very much. This is exactly what is needed. It was the collapse-height concept that I was missing.
This works well. Can you explain in what respect you designate this as stupid? It's certainly non-standard practice, but I find it is better to accede to these requests from my colleague than argue him out of it!
Andrew
On 25 May 2018 at 01:21, David Kastrup <address@hidden> wrote: