internal ReplaceAILinkOperation(AIUI ui, Guid oldValue, Guid newValue, AILinkView target)
     : base(ui)
 {
     _target   = target;
     _oldValue = oldValue;
     _newValue = newValue;
 }
 internal RemoveAILinkOperation(AIUI ui, AILinkView target)
     : base(ui)
 {
     _target = target;
 }