Update WindowAcrylicBlur.cs

Author: yanjinhuagood

src/WPFDevelopers.Shared/Controls/Windows/WindowAcrylicBlur.cs

@@ -4,6 +4,7 @@
 using System.Windows.Interop;
 using System.Windows.Media;
 using Microsoft.Win32;
+using WPFDevelopers.Helpers;
 #if NET40
 using Microsoft.Windows.Shell;
 using WPFDevelopers.Helpers;