Include this in your program and it will throw the dump.
data:begin of wa_mara,
matnr type matnr,
END OF wa_mara.
data it_mara like TABLE OF wa_mara.
INITIALIZATION.
select matnr from mara into TABLE it_mara where matnr in s_matnr.
loop at it_mara into wa_mara.
s_matnr-low = wa_mara-matnr.
s_matnr-sign = 'I'.
s_matnr-option = 'EQ'.
append s_matnr.
ENDLOOP.
at selection-SCREEN output.
loop at screen.
if screen-name = 'S_MATNR-LOW' or screen-name = 'S_MATNR-HIGH'.
screen-input = 0.
MODIFY SCREEN.
ENDIF.
ENDLOOP.