Thread:Extension talk:CategoryTree/ + hidden

Hi I have MediaWiki 1.18 and the related CategoryTree r100383. I use Firefox 11.0 (and Chrome 18), both with Javascript enabled. Using CategoryTree only shows 1 level (the root and all children) without any [+]. When I see the HTML code : ...  ...

So, why there is "display:None" ? When I disable that on the root element, it appears [-] but it isn't active.

What's append ? How to fix that ?

Thanks in advance for your answer.