back button is not working-urgent

hi all,

in my program back button is working. now i have a button in application tool bar i.e. execution(F8) button when i am executing this button it has to show the data from ztable.

but it is not working fine.

its sy-ucomm is execute in debug it is showing the data correctly but it not showing when i press f8 button anybody can help in this.

i am sending my code .

report zmahi4.

TABLES: sscrfields.

DATA : IT_SECOBJECTS LIKE ZUSER_SECOBJECTS OCCURS 0 WITH HEADER LINE .

selection-screen: begin of block b1.

parameters : p_appln type mara-matnr.

parameters : p_user type marc-werks.

selection-screen: end of block b1.

data: begin of exclude occurs 0,

func(10) type c,

end of exclude.

AT SELECTION-SCREEN.

CASE sscrfields-ucomm.

WHEN 'BACK' or 'EXIT'.

SET SCREEN 0.

LEAVE SCREEN.

WHEN 'EXECUTE'.

SELECT * FROM ZUSER_SECOBJECTS

INTO TABLE IT_SECOBJECTS.

CHECK SY-SUBRC EQ 0.

LOOP AT IT_SECOBJECTS.

WRITE : IT_SECOBJECTS.

ENDLOOP.

WHEN OTHERS.

ENDCASE.

At selection-screen output.

• set pf-status 'SELK'. <-- Comment this line

if sy-dynnr eq '1000'.

call function 'RS_SET_SELSCREEN_STATUS'

exporting

p_status = 'SELK'

tables

p_exclude = exclude

exceptions

others = 1.

endif.

CASE SY-UCOMM.

WHEN 'EXECUTE'.

PERFORM GET_DATA.

endcase.

&----

*& Form GET_DATA

&----

• text

----

• --> p1 text

• <-- p2 text

----

form GET_DATA.

• SELECT * FROM ZUSER_SECOBJECTS

• INTO TABLE IT_SECOBJECTS.

*CHECK SY-SUBRC EQ 0.

*LOOP AT IT_SECOBJECTS.

*WRITE : IT_SECOBJECTS.

*ENDLOOP.

endform. " GET_DATA

thanks,

maheedhar.t