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using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Windows;using System.Windows.Controls;using System.Windows.Data;using System.Windows.Documents;using System.Windows.Input;using System.Windows.Media;using System.Windows.Media.Imaging;using System.Windows.Navigation;using System.Windows.Shapes;using Telerik.Windows.Controls;namespace MainWindowInBackground{ /// <summary> /// Interaction logic for MainWindow.xaml /// </summary> public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); } private void Button_Click(object sender, RoutedEventArgs e) { RadWindow l_hostWindow = new RadWindow() { Owner = System.Windows.Application.Current.MainWindow, WindowStartupLocation = WindowStartupLocation.CenterOwner, Content = "Test" }; l_hostWindow.Show(); MessageBox.Show("MessageBox", "MessageBox", MessageBoxButton.OK, MessageBoxImage.Information, MessageBoxResult.OK); } }}