hellosam.net.collections (nuget): ObservableDictionary based on AVLTree with O(log N) insert/removal operations.  Collection event aren't "Reset" but with proper positioning so it can be bound to the UI without affecting sort/group/highlight position on update.  Source code, usage and example can be found at https://github.com/sam0737/hellosam.net.collections  (Observable Dictionary, Observable Collection)
Keywords: wpf|observable|collection|dictionary|avltree|INotifyCollectionChanged|ObservableCollection|ObservableDictionary