So I've done a bit more digging and found a bit of correlation between my portals. The layout has the following:
Left Portal is based on a table called Vinegars and has the following fields:
The right portal is based on a table called Vinegar details and has the fields:
Now these two tables are joined by a 1 to 1 relation through a _KP_VinegarID. They are based on the same table but have different table occurance names.
The fields that don't show up are Name, Type and Number in IWP.
Name, Type and Number in which portal?
Typically, there's a script used to "synch" such "Master/Detail" portals. There may be a need to insert an extra Commit record step into that script before it works in IWP--and that can play havoc with keeping the right focus on clicked portal rows.