add AboutWindow

HandyControlDemo/ViewModel/WindowDemoViewModel.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Windows;
 using GalaSoft.MvvmLight.CommandWpf;
 using HandyControlDemo.Tools;
 
@@ -12,6 +13,7 @@ namespace HandyControlDemo.ViewModel
         {
             if (AssemblyHelper.CreateInternalInstance($"Window.{windowTag}") is System.Windows.Window window)
             {
+                window.Owner = Application.Current.MainWindow;
                 window.ShowDialog();
             }
         }