Category-tree needs to load in parts (AJAX?)
We have a wide category-tree with around 6 levels of hierarchy and summing up to around 40.000 entries at the moment. This leads to performance-problems with various brokers (loading stalls until browser-timeout, ...). This could be solved if for example only the next level would be loaded at one time but not all subtrees at once. If you then open a collapsed branch that would load more data via AJAX.