The relationship of that portal allows you to create Invoice item records? Yoy are in browse mode. You enter the new invoice line data in the last 'blank' row of the portal. You enter data in the new 'blank' row, and the previously-entered data is still there, now showing in the row above?
Then when you commit the record, by clicking in the background of the Invoice record, the portal's contents disappear? But if you navigate to the Invoice Items table and search for them they are there?
I assume the relationship is by InvoiceID. On the Invoice layout I would put the Invoice ID right beside the portal. In each portal row I would put the InvoiceID from the Items table. In the Items Table layout I would have both of those IDs as well, and then see where they do not match.
Are you sure there isn't a script trigger that is running OnRecordCommit?
Is this FileMaker 11 that you are using? If so, is it possible that there's a portal filter set up that filters out the records and thus keeps them from re-appearing in your portal? Enter layout mode, double click the portal and see if the Portal filter check box is selected.
Thanks for your help.
I found the mistake. The Invoice item records disappeared from the portal so easily because in my Invoice table the InvoiceID field was set to "generate upon entry" instead of "generate upon creation". So each time I began with a new Invoice the Invoice items could not be referenced because no InvoiceID field had been created. Quite tricky, but I learned a lot from it.
So thanks again for your help in this matter.