I believe your issue can be demonstrated using this snippet which does not compile without addition of start-of-selection.
- *----------------------------------------------------------------------*
- CLASS mainclass DEFINITION.
- PUBLIC SECTION.
- CLASS-METHODS main.
- ENDCLASS. "mainclass DEFINITION
- *----------------------------------------------------------------------*
- CLASS mainclass IMPLEMENTATION.
- METHOD main.
- WRITE 'hello'.
- ENDMETHOD. "main
- ENDCLASS. "mainclass IMPLEMENTATION
- START-OF-SELECTION.
- mainclass=>main( ).
/.