I added a drop down field named "Warranty" to the "InvoiceLine" table. The dropdown pulls from another table with warranty periods. I then added this field to the InvoiceLineItems grid in the Invoice screen and publish. The screen shows the new drop down witht the list contents correctly. I select a value and then click update to save the row. The value is displayed in the row correctly at this point. I then save the invoice and clear the screen. I return to the original invoice and notice that the value I selected is no longer there but blank.