Thread:Project:Support desk/Tabber doe not work

I'm trying to use Extension:Tabber, it does not work for me. please help Thanks. what I have: MediaWiki 	1.19.0 PHP 	5.3.3 (apache2handler) MySQL 	5.1.52 Tabber (Version 1.2) <== Extension:Tabber installed

code: a=a b=b

it shows: a

b