private void chkHistory_Checked(object sender, RoutedEventArgs e)
 {
     try
     {
         if (CDeclaration.IsBusy || CPerformDrop.IsBusy)
         {
             MessageBox.ShowBox("MessageID368", BMC_Icon.Information);
             e.Handled = false;
             return;
         }
         chkHistory.IsEnabled = false;
         pnlDropContent.Children.Clear();
         CDropHistory history = new CDropHistory();
         pnlDropContent.Children.Add(history);
         history.Margin = new Thickness(0);
     }
     finally
     {
         chkHistory.IsEnabled = true;
     }
 }
 private void chkHistory_Checked(object sender, RoutedEventArgs e)
 {
     try
     {
         if (CDeclaration.IsBusy || CPerformDrop.IsBusy)
         {
             MessageBox.ShowBox("MessageID368", BMC_Icon.Information);
             e.Handled = false;
             return;
         }
         chkHistory.IsEnabled = false;
         pnlDropContent.Children.Clear();
         CDropHistory history = new CDropHistory();
         pnlDropContent.Children.Add(history);
         history.Margin = new Thickness(0);
     }
     finally
     {
         chkHistory.IsEnabled = true;
     }
 }