fixed a bug of BlurWindow

HandyControlDemo/UserControl/Main/LeftMainContent.xaml

@@ -4,7 +4,7 @@
         x:Class="HandyControlDemo.UserControl.LeftMainContent"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:data="clr-namespace:HandyControlDemo.Data"
-        Background="Transparent"
+        Background="{Binding Background,RelativeSource={RelativeSource FindAncestor,AncestorType=Window}}"
         xmlns:controls="clr-namespace:HandyControl.Controls;assembly=HandyControl"
         xmlns:langs="clr-namespace:HandyControlDemo.Properties.Langs"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation">

HandyControlDemo/UserControl/Main/NoUserContent.xaml

@@ -70,7 +70,7 @@
         <Border Background="{DynamicResource SecondaryRegionBrush}" CornerRadius="4" Margin="16" Effect="{StaticResource EffectShadow2}">
             <StackPanel Orientation="Horizontal">
                 <StackPanel Button.Click="ButtonLangs_OnClick" Margin="10,10,0,10">
-                    <Button Tag="cn" Style="{StaticResource ButtonCustom}">
+                    <Button Tag="zh-cn" Style="{StaticResource ButtonCustom}">
                         <Image Width="32" Source="/HandyControlDemo;component/Resources/Img/Flag/cn.png"/>
                     </Button>
                     <Button Tag="en" Style="{StaticResource ButtonCustom}" Margin="0,10,0,0">