Thread:Talk:MediaWiki/Categories in mediawiki sidebar in Vector skin

How to show categories and subcategories in sidebar of Mediawiki 1.20.3 in Vector skin. Please help me please.I have used CategoryTree extension but dont know syntax is rightly used in LocalSettings.php  I got one website using this http://edutechwiki.unige.ch/fr/Accueil

Please tell me how to dislpaly categories in vector skin?