private void toolStripButtonDesign_Click(object sender, EventArgs e)
 {
     if (treeViewReports.SelectedNode.Index != -1)
     {
         using (Stimulsoft.Report.StiReport report = new Stimulsoft.Report.StiReport())
         {
             report.Load(ReportsPath + treeViewReports.SelectedNode.Text + ".mrt");
             report.Dictionary.Databases.Clear();
             report.RegData("Demo", "Demo", dataSetInvoice);
             report.Compile();
             report.Design(true);
         }
     }
     else
     {
         MessageBox.Show("Select invoice first to proceed!");
     }
 }