Multi-join relationship - Fun!
This problem has bugged me for almost a year. Feels like one of those brain-teaser problems that require an off-the-wall solution.
Take 2 tables, that each have 2 fields that form their primary keys. But, only one of the fields can be used to relate the two tables. Now, create a 3rd table, with 3 fields that form the primary key, but only 2 of it's fields can be used to relate to the other two tables.
Now, with a layout based on table 1, and a portal based on table 2, try to auto-create records in the 3rd table through fields placed on the portal. Problem is, the inability to pass a field from the layout's table through the portal table to create the record in the final table.
Permanent Kudos to whoever can get this to work in FM9. Attached sample DB should get you started.