add FocusVisualStyle for some controls

src/Shared/HandyControlDemo_Shared/MainWindow.xaml

@@ -15,9 +15,9 @@
                      OtherButtonHoverForeground="White"
                      OtherButtonForeground="White"
                      Style="{StaticResource WindowBlur}"
-                     WindowState="Maximized"
                      Title="MainWindow" 
                      ResizeMode="CanResizeWithGrip"
+                     WindowStartupLocation="CenterScreen"
                      Name="MyWindow"
                      DataContext="{Binding Main,Source={StaticResource Locator}}"
                      hc:Dialog.Token="{x:Static data:MessageToken.MainWindow}"