Back Button works one way for execute and another for enter

Question

I created a custom program that includes a selection screen and a detailed list/table output.  When a user enters their selection criteria and hits enter (instead of execute) they'll go to the next screen, and when they are ready to back out, it goes back to the selection screen, which is correct.  But when a users enters their selection criteria and hits the Execute button, they'll go to the detailed screen and when they press the back button, it backs out of the program completely.  I don't understand why their is a difference between the two and how it would affect the back button.  Also, I don't know how to get the execute button and the enter key to act the same way.  Can any one offer any suggestions?

Answer 1

For the create program the selection screen logic is as follows:
parameters: s_matnr1 like mara-matnr,
             s_kunnr like kna1-kunnr.
start-of-selection.
at selection-screen on s_matnr1.
  if s_matnr1 is initial.
    message i080(zc) with 'Material number is required' .
    flag_error = 'Y'.
  endif.
LOOP at s_matnr1 to flag all invalid materials. Display message.
  select matnr
    from mara up to 1 rows
     into mara-matnr
     where matnr eq s_matnr1.
  endselect.
  if sy-subrc ne 0.
    message e080(zc) with 'Invalid Material'.
  endif.
  clear:   process_kunnr,
           process_matnr,
           zkotg903_excpts_tab,
           no_kunnr.
  refresh: process_kunnr,
           process_matnr,
           zkotg903_excpts_tab.
at selection-screen on s_kunnr.
  if s_kunnr is initial.
    no_kunnr = 'Y'.
  else.
    no_kunnr = 'N'.
    select kunnr from kna1 up to 1 rows
       into kna1-kunnr
       where kunnr eq s_kunnr.
    endselect.
    if sy-subrc ne 0.
      message e080(zc) with 'Invalid Customer'.
    endif.
  endif.
  perform get_material.
  loop at process_matnr.
    move process_matnr-matnr to zkotg903_excpts_tab-matnr.
    if no_kunnr = 'N'.
      select kunnr
        from kna1
        into  table process_kunnr
         where kunnr eq s_kunnr.
    endif.
    if sy-subrc = 0.
      loop at process_kunnr.
        select *
          from zkotg903_excpts
          where matnr = process_matnr-matnr
          and   kunnr = process_kunnr-kunnr.
        endselect.
        if sy-subrc <> 0.   
  move process_kunnr-kunnr to zkotg903_excpts_tab-kunnr.
          zkotg903_excpts_tab-datbi = '99991231'."validity end date
          zkotg903_excpts_tab-datab = sy-datlo.  "validity begin date
          zkotg903_excpts_tab-zzuname = sy-uname.
          append zkotg903_excpts_tab.
        else.
          message i318(zc) with process_kunnr-kunnr
             process_matnr-matnr.
          flag_error = 'Y'.
        endif.
      endloop.        "endloop for kunnr
    else.
      message i190(zc) with s_matnr1+3.
      flag_error = 'Y'.
    endif.
  endloop.           "endloop for matnr
if there isn't a customer, append material to zkotg903_excpts_tab.
  if no_kunnr = 'Y'.
    append zkotg903_excpts_tab.
  endif.
  if flag_error = 'N'.
    call screen '100'.
  else.
    call selection-screen 1000.
  endif.
The maintenance program is a little less involved as I am sure you know.  If you would like to see that code as well, I can post it.