VMS Help UIL, Compile Time Errors, DUP_LIST  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  ERROR:  A  widget  or  gadget  declaration  can  have  at  most  one
  arguments list, one callbacks list, and one controls list.

  USER ACTION:  If you wish to specify multiple  lists  of  arguments,
  controls,  and  callbacks,  you  can  do  so  within  one list.  For
  example:
         arguments { arguments_list1; arguments_list2; };