Flushes the Undo and Redo stacks.
Role: This method flushes the Undo and Redo stacks.
The Undo/Redo mechanism is freezed until a new UI transaction is created.
Modifications done while the Undo/Redo mechanism is freezed will not be undoable.
Returns:
Returns always S_OK.
This object is included in the file: CATAfrUndoRedoServices.h