bool
true if undo/redo is supported, otherwise false
Determines whether this hierarchy node type handler supports undo/redo operations. When doing certain operations
that modify the hierarchy, for example reordering nodes with mixed-types, the hierarchy needs to know if the involved node type handlers
support undo/redo in order to determine whether to create an undo operation for the changes specific to the hierarchy.
Return true if this node type handler has underlying data that supports undo/redo.
Return false if this node type handler has underlying data that does not support undo/redo.