Prevented the tree sorter failing if a tree helper is not required and hence not injected leaving the root node array unset.
Prevented the tree sorter failing if a tree helper is not required and hence not injected leaving the root node array unset.

TheLanguageArchive/Arbil,TheLanguageArchive/Arbil,TheLanguageArchive/Arbil,TheLanguageArchive/Arbil,TheLanguageArchive/Arbil