FMPro v 8.0, Mac OSX

I'm posting this in case it saves someone else some time and frustration:

A few weeks ago I asked a question about sorting and grouping records
for a report: I wanted to group records by client name (so as to put
client info in a subsummary header), but sort them by a different field,
certificate number.

A few days after, I discovered that FMP (at least from v8) provides a
way to do exactly what I want. In the Sort Records... dialog is a
check-box for "Reorder Based on Summary Fields". I added a field to my
table that summarizes on 'minimum of certificate_number' - and then
spent days trying to figure out why it didn't work.

My databases are designed with layouts and scripts in one file, and all
the tables and data in another (or multiple others). It turns out that,
for "Reorder Based on Summary Fields" to work, the table containing the
summary field must be in the same file as the layout doing the sorting.
Once I figured that out it was simple to create a temporary table in the
layouts file, import relevant records from the Certificates table and
relate it back to the Clients table.

I don't know if this bug affects other versions of FMP or other
operating systems, and I couldn't find a mention of it in the FMP
knowledge base. I'm passing it on here as a 'for-what-it's-worth'.