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

       /BLOCK (D)

    Specifies that the comment should be entered above the cursor
    (or selected text range), formatting the comment according to the
    placeholder LSE$BLOCK_COMMENT.

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