If you ever wanted to restrict the possibilities of Select-Options, there is good news. 
The FM 'SELECT_OPTIONS_RESTRICT' is the way to go.
 
#---------------------------------------------------------------------*
*# Sortierung-Options restrict to EQ 
  DATA: L_WA_RESTRICT TYPE SSCR_RESTRICT,
        L_WA_OPTLIST  TYPE SSCR_OPT_LIST,
        L_WA_ASS      TYPE SSCR_ASS.
* Only 'EQ' 
  L_WA_OPTLIST-NAME = 'OBJECTKEY1'.
  L_WA_OPTLIST-OPTIONS-EQ = 'X'.
  APPEND L_WA_OPTLIST TO L_WA_RESTRICT-OPT_LIST_TAB.
  L_WA_ASS-KIND = 'S'.
  L_WA_ASS-NAME = 'S_SORT'.
  L_WA_ASS-SG_MAIN = 'I'.
  L_WA_ASS-SG_ADDY = SPACE.
  L_WA_ASS-OP_MAIN = 'OBJECTKEY1'.
  APPEND L_WA_ASS TO L_WA_RESTRICT-ASS_TAB.
  CALL FUNCTION 'SELECT_OPTIONS_RESTRICT'
    EXPORTING
      RESTRICTION = L_WA_RESTRICT.
  IF SY-SUBRC <> 0.
* Implement suitable error handling here
  ENDIF.
Serkan AKKAVAK
Computer Engineer
ABAP Developer & SAP S/4 HANA Logistics Team Lead
Contact : serkurumsal@yandex.com
 
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