Version 10.5 spreadsheet option in list page

I migrated a project from 10.4 to 10.5 and would like to use the spreadsheet option feature in the list page. I selected the spreadsheet option and automatic add record option but it seems not working. All the existing records are opened for edit but I could not make it automatically add new records after pressing tab in the last field of the last record. Could anyone help? Thanks.
Jack Tong