You can use the Name box in the inspector's position tab to give both tab panels an object name.
Then the onRecordLoad trigger can use the Go to Object script step to automatically select one of the two panels depending on the value in this other field.
That makes sense to me and is great while working. Thank you!
But if I wanted to print a batch of records that had these alternating tabs, would some records print with the one tab while others would print with the other based on this checkbox? I suspect not. I can script my printing to sort, choose, print one and then the next, but this feels like a bit of a workaround.
But you've given me the main thing I need. Thank you!
You are correct. It's a rather odd fact of FileMaker design that selecting a particular tab panel selects it for all records in your found set. In form view, you can only see one record at a time so this is OK, but in list view or when printing, not so good.
In that situation, you might need a layout designed expressly for printing where a portal filter makes one of the two portals empty depending on the value in that other field. You can then either layout transparent portals and fields or set them to slide up/resize on your print layout.