private void btLoad_Click(object sender, RoutedEventArgs e)
        {
            if (viewer.Report != null)
            {
                OpenFileDialog fileDilalog = new OpenFileDialog();
                fileDilalog.Filter = "*.xml|*.xml";

                if (fileDilalog.ShowDialog() == true)
                {
                    Stimulsoft.Report.StiReport report = viewer.Report;
                    viewer.Report = null;

                    var stream = fileDilalog.File.OpenRead();
                    report.LoadEditableFields(stream);

                    stream.Close();
                    stream.Dispose();
                    stream = null;

                    viewer.Report = report;
                }
            }
        }