Javascript height animation problem

I am working on a php-based CMS-like system (with an included shop) and have hit a wall while creating the navigation. The navigation has an unlimited amount of categories with unlimited amounts of subcategories (over unlimited amounts of levels) and that seems to cause problems while animating the navigation.

The navigation is basted on HTML lists and whenever i want to animate something on level 4 (and deeper) the parent lists fail to resize with the child list.

Right now the navigation is created dynamically (every subcategory is dynamically loaded after clicking the parent etc.) but i've also tried doing it completely without lists, only divs and i've also tried generating all elements server-side and hiding them. I've also tried doing it with and without jQuery 开发者_Python百科but nothing helped.

You can take a look at it here: http://shop.ipron.info/shop/ (Most of the variables/comments are in german so if needed i can provide understandable versions of those)

The behaviour is the same in all browsers i was able to test so i assume there is some error on my side i haven't been able to spot.

Any help is appreciated.

You code hits this error an infinite amount of times:

Uncaught TypeError: Cannot call method 'removeChild' of null

The error occurs in Navigation.js on line 138