Apply the WHERE clause.
BUTTON1:
   listid=makelist();
   listid=insertc(listid, "Sex='M'" ,-1);
   listid=insertc(listid, "and weight > 50", -1);
   call putlist(listid, 'WHERE clause', 0);
   call send(tabid, '_setWhere', listid);
   rc=clearlist(listid);