Added: New public API, IHierarchyNodeTypeHandlerViewModelState, and GetOrCreateHandlerState<T>, TryGetHandlerState<T> and DestroyHandlerState on HierarchyViewModel, for node type handler state that belongs to a single view model. HierarchyNodeTypeHandlerBase.SearchBegin, SearchMatch and SearchEnd gained overloads taking the HierarchyViewModel running the search.
ScriptingAPI change