SAP/ABAP: MODIF ID

SELECTION-SCREEN BEGIN OF BLOCK TEST1 WITH FRAME TITLE TEXT-002.
 SELECT-OPTIONS: SO_TARIH FOR S121-SPTAG MODIF ID R11,
 SO_MALGR FOR MARA-MATKL.
 PARAMETERS: PA_HAFTA LIKE S121-SPWOC MODIF ID R12,
 PA_AY LIKE S121-SPMON MODIF ID R13.

SELECTION-SCREEN END OF BLOCK TEST1.

AT SELECTION-SCREEN OUTPUT.

if pa_ay eq 'X'.

LOOP AT SCREEN.

CASE SCREEN-GROUP1.
 WHEN 'R13'.
 SCREEN-INPUT = '1'.
 SCREEN-OUTPUT ='1'.
 SCREEN-ACTIVE = '1'.

WHEN 'R12'.
 SCREEN-INPUT = '0'.
 SCREEN-OUTPUT ='1'.
 SCREEN-ACTIVE = '1'.
 WHEN 'R11'.
 SCREEN-INPUT = '0'.
 SCREEN-OUTPUT ='1'.
 SCREEN-ACTIVE = '1'.

ENDCASE.
 MODIFY SCREEN.
 ENDLOOP.

elseif ......... .

endif.