'POPUP_GET_VALUES'的金额字段如何不为灰色

REPORT  z_barry_test .

DATA: netpr LIKE ekpo-netpr ,
      itab LIKE sval OCCURS 0 WITH HEADER LINE .

itab-tabname = 'EKPO'.
itab-fieldname = 'EBELN'.
APPEND itab.
itab-tabname = 'EKPO'.
itab-fieldname = 'NETPR'.
APPEND itab.
itab-tabname = 'EKKO'.
itab-fieldname = 'WAERS'.
*itab-FIELD_ATTR = '04'.
APPEND itab.

CALL FUNCTION 'POPUP_GET_VALUES'
  EXPORTING
    popup_title     = 'TEST'
  TABLES
    fields          = itab
  EXCEPTIONS
    error_in_fields = 1
    OTHERS          = 2.

READ TABLE itab INDEX 2 .
netpr = itab-value .
WRITE netpr.