TreeWalker objects are used to navigate a document tree or subtree using the view of the document defined by their whatToShow flags and filter if any. Any function which performs navigation using a TreeWalker will automatically support any view defined by a TreeWalker....TreeWalker objects are used to navigate a document tree or subtree using the view of the document defined by their whatToShow flags and filter if any. Any function which performs navigation using a TreeWalker will automatically support any view defined by a TreeWalker.