with a content structure large enough, the cookie ContentStructureMenu will grow bigger than the 4096 char defined in RFC 2965.

there is a new standard, RFC 6265 that changes the cookies requirements, it deprecates the previous stardard, but the release of 6265 is still too young to apply to many browsers, proxies, firewalls and other software that is expecting cookies with maximum of 4k size.

to reproduce:
1 - create 5 folders below root
2 - create 5 more inside the each of first five
3 - repeat until level 5

open firebug or favourite cookie watch tool:
keep watching the ContentStructureMenu cookie. start opening folders*, select folders each time deeper and deeper in diferent trees. watch how the cookie stores all the open trees.

• note: do close close the folders, or they will be removed from the cookie.

eventually, with a large and deep enough structure, the cookie will grow beyond 4096 chars, which can cause the cookie to be blocked by browsers, webservers, proxies, etc.