[pmwiki-users] (german) install. problem: SideBar-Handling

[WvL]

Hi [[pm]]list,

as a "new-to-pmwiki" user i am trying a (german) internationalisation,
steps as follows:
- blank standard (english) install
- copy all  i18n/wikilib.d/PmWikiDe.*  into  wikilib.d
- in config.php, at the end add line:
 XLPage('de','PmWikiDe.XLPage');
- i edited the default sidebar 'Site.SideBar' and "translated" links as follows:
  e.g.: [[PmWiki/PmWiki]]  into  [[PmWikiDe/PmWikiDe]]

After saving, click on [[PmWikiDe/PmWikiDe]] switches from the 
previous (default) sidebar 'Site.SideBar' to (the contents of) 'PmWikiDe.SideBar' ...

In PmWikiDe.SideBar i edited and changed:
  (:include Main/SideBar:)  into  (:include Site/SideBar:)
(which in turn then results to the same
 as on http://www.pmichaud.com/wiki/PmWikiDe/PmWikiDe)

My Remarks/Questions:
(1) Should "the sidebar" not always/ever belong to group 'Site' ?
(2) Which file/module/setting initiates the switching of the SideBar-group ?
(3) Generally: what is the recommended concept behind providing pmwiki-Menus/SideBars?
    Should every group have his own SideBar-page (danger of recursion?)
    or 1 SideBar-page for all groups?

Thanx in advance,
WvL
PS: i personally would prefer deep/nested groups (up to a practical depth/TOC-level of say 4)
    associated with 1 tree-menu (dynamically reflecting all saved member-pages of her groups)
    - but i saw some comments/cookbook-recipes on this already formerly discussed issues ...