Compiler Error Message: CS0234: 

First I wanted to thank you for your efforts in this great work, it's really valuable, useful and complete for a scenario where you have to manage many users.
I have found that when creating new groups, roles are listed alphabetically which facilitates location and allocation of roles that need to be assigned, but not so with the user accounts, groups needed to assign accounts, are not sorted, this can be cumbersome for scenarios where there is a hundred groups , would be a big problem to locate the group you need to assign to a particular user account. Please I would appreciate very much if you can also order the groups to create a new user account.
The sample application has been running perfectly in Visual Studio 2013 - SP3, today when I upgraded to SP4 , it turns out that no longer works reported an error that states that:
Compilation Error 
  Description: An error occurred during the compilation of a resource required to service this request. Please review the following specific error details and modify your source code appropriately. 

 Compiler Error Message: CS0234: The type or namespace name 'Ajax' does not exist in the namespace 'System.Web.Mvc' (are you missing an assembly reference?)

Source Error:
Line 22:     using System.Web.WebPages;
Line 23:     using System.Web.Mvc;
Line 24:     using System.Web.Mvc.Ajax;
Line 25:     using System.Web.Mvc.Html;
Line 26:     using System.Web.Optimization;
Source File: c:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\root\6f39afb6\14a07bc9\App_Web_index.cshtml.a8d08dba.zcgj68j1.0.cs    Line: 24

I can not figure out why is happening and I should not know how to solve it.

Sorry if this is not how or where to submit this question, and I appreciate a lot if you can tell me where and how to present this concern.

Thank you very much