Library /sys$common/syshlp/lse$clihelp.hlb ENTER, COMMENT, Qualifiers, /LINE  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Specifies that the comment should be entered at the end of the
    current line (or selected text range), formatting the comment
    according to the placeholder LSE$LINE_COMMENT.

    You cannot specify both the /LINE and /BLOCK qualifiers.