public void LoadGroupFromXmlFile(string file)
        {
            XmlDocument doc = new XmlDocument();

            doc.Load(file);
            if (string.CompareOrdinal(doc.DocumentElement.Name, "MathGroup") == 0)
            {
                LoadGroupFromXmlNode(doc.DocumentElement);
            }
            else if (doc.DocumentElement.Name == XmlSerialization.XML_Math)
            {
                MathExpEditor mathExpEditor1 = new MathExpEditor();
                mathExpEditor1.LoadFromXmlNode(doc.DocumentElement);
                this.AddMathViewer(mathExpEditor1.MathExpression);
            }
        }
 public void SetMathEditor(MathExpEditor editor)
 {
     _editor = editor;
 }