temporary hack version:
public FixedDocumentElementBase Clone()
        {
            RadFixedPage newPage = new RadFixedPage
            {
                Size = Size,
                Rotation = Rotation
            };
            foreach (var c in Content)
            {
                c.SetParent(newPage);
                newPage.Content.Add(c);
            }
            // not sure about this.
            foreach (var annotation in Annotations)
            {
                annotation.SetParent(newPage);
                newPage.Annotations.Add(annotation);
            }
            return newPage;
        }