After installing the latest EPiServer CMS 6 R2 patch http://world.episerver.com/Articles/Items/EPiServer-CMS-6-R2--Update/ comparing versions of pages result in a 500 error.

The stack trace shows a method that migth have been added in this latest patch to deal with IE10-11 issues, and this test seems to fail because Request.Useragent is null.

Error log shows a request to

http://localhost/UI/CMS/edit/PageCompare/VisualPageCompare.aspx?first=2404_46716&second=2404_46012&firstVersionNumber=11&secondVersionNumber=10

Part of stack trace:

System.ArgumentNullException: Value cannot be null.

Parameter name: input
at System.Text.RegularExpressions.Regex.Match(String input)
at EPiServer.Web.PageExtensions.ContextMenu.get_InternetExplorerVersion()
at EPiServer.Web.PageExtensions.ContextMenu.SetupOnPageEdit()
at EPiServer.Web.PageExtensions.ContextMenu.RegisterMenuScripts(Object sender, EventArgs e)
at System.EventHandler.Invoke(Object sender, EventArgs e)
at System.Web.UI.Page.OnInit(EventArgs e)
at EPiServer.PageBase.OnInit(EventArgs e)