WRITE STATEMENT IS GETTING EXECUTED BUT NOT GETTING DISPLAYED

Question

HII All,
i hv created a selection screen with push button. Now when i m clicking that pushbutton, output is not getting displayed..when i debug program ,control enters in switch case and also executes write statement but write statement is not getting displayed.. below is the code ..
SELECTION-SCREEN BEGIN OF BLOCK INPUT WITH FRAME TITLE TEXT-001.
  SELECTION-SCREEN PUSHBUTTON 10(20) TEXT-002  USER-COMMAND FIR.
  SELECTION-SCREEN PUSHBUTTON 35(20) TEXT-003  USER-COMMAND SECOND.
SELECTION-SCREEN END OF BLOCK INPUT.
       WA-EMP_NO = 123.      
        WA-EMP_CO = 'A'.
        WA-EMP_N = 'APOORV'.
        APPEND WA TO IT_TAB.
AT SELECTION-SCREEN.
CASE SY-UCOMM.
WHEN 'FIR'.
PERFORM SUB1.
WHEN 'SECOND'.
        APPEND LINES OF IT_TAB FROM 2 TO 3 TO IT_TAB1.
        WRITE:/ 'SECOND INTERNAL TABLE CONTENTS'.
        LOOP AT IT_TAB1 INTO WA1.
        WRITE:/15 SY-TABIX, WA1-EMP_NO NO-ZERO, WA1-EMP_CO, WA1-EMP_N.
        ENDLOOP.
ENDCASE.
FORM SUB1.
LOOP AT IT_TAB INTO WA.
          WRITE:/ SY-TABIX, WA-EMP_NO NO-ZERO, WA-EMP_CO, WA-EMP_N.
ENDLOOP.
ENDFORM.
Plz help me..
Edited by: Julius Bussche on Jan 29, 2009 1:40 PM
Code tags added and please dont use Caps-Lock.

Answer 1

HI,
SELECTION-SCREEN BEGIN OF BLOCK INPUT WITH FRAME TITLE TEXT-001.
SELECTION-SCREEN PUSHBUTTON 10(20) TEXT-002 USER-COMMAND FIR.
SELECTION-SCREEN PUSHBUTTON 35(20) TEXT-003 USER-COMMAND SECOND.
SELECTION-SCREEN END OF BLOCK INPUT.
WA-EMP_NO = 123.
WA-EMP_CO = 'A'.
WA-EMP_N = 'APOORV'.
APPEND WA TO IT_TAB.
* AT SELECTION-SCREEN.                 "Comment this
START-OF_SELECTION.                     " Add this
CASE SY-UCOMM.
WHEN 'FIR'.
PERFORM SUB1.
WHEN 'SECOND'.
APPEND LINES OF IT_TAB FROM 2 TO 3 TO IT_TAB1.
WRITE:/ 'SECOND INTERNAL TABLE CONTENTS'.
LOOP AT IT_TAB1 INTO WA1.
WRITE:/15 SY-TABIX, WA1-EMP_NO NO-ZERO, WA1-EMP_CO, WA1-EMP_N.
ENDLOOP.
ENDCASE.
FORM SUB1.
LOOP AT IT_TAB INTO WA.
WRITE:/ SY-TABIX, WA-EMP_NO NO-ZERO, WA-EMP_CO, WA-EMP_N.
ENDLOOP.
ENDFORM.