jQuery Treeview is very nice lightweight and flexible transformation of an unordered list into an expandable and collapsable tree, great for unobtrusive navigation enhancements. Supports both location and cookie based persistence.
When I started using Treeview I found problem with pre-opening child nodes. While first level nodes are pre-opening just fine, the chidren of parent nodes do not shows up.
The problem is in prepareBranches function, where script hides all nodes which don't have 'open' class.
Yes, as you probably suspect it hides also parents of node which has this 'open' class.