<?xml version="1.0"?>


current page : 1
--------------------
  dump union : "document,group,"
  union-last : group
  union-last (without /root) : group
  preceeding-sibling 
  parent-group group
  root document
-----------------------


current page : 2
--------------------
  dump union : "document,group,page,"
  union-last : page
  union-last (without /root) : page
  preceeding-sibling page
  parent-group group
  root document
-----------------------


current page : 3
--------------------
  dump union : "document,group,page,"
  union-last : page
  union-last (without /root) : page
  preceeding-sibling page
  parent-group group
  root document
-----------------------


current page : 4
--------------------
  dump union : "document,group,page,"
  union-last : page
  union-last (without /root) : page
  preceeding-sibling page
  parent-group group
  root document
-----------------------