Voucher Match Header Fields Protected on Exit

Does anyone know why the Voucher Date, G/L Date and Invoice Number fields are now protected in E1 Version 9 when you exit the header in the screen? Users are finding that an annoyance when they access the Receipts to Match form exit and then back out of it. They can't change the data in these fields on the voucher form without backing out of the application entirely and starting over.