Only IE10 returning Invalid Postback - asp.net

Question

I swear I have a love hate relationship with Microsoft. This is being thrown only in IE 10.
Invalid postback or callback argument. Event validation is enabled using <pages enableEventValidation="true"/>
Now,
On the #page I have ValidateRequest = "False"
In the Web.config I have httpRuntime requestValidationMode="2.0"
I am NOT using any Ajax or have a ScriptManager
I am checking for PostBack
Removed combobox code but it does use AutoPostBack
Here is my code
Private Sub Page_Init(sender As Object, e As EventArgs) Handles Me.Init
Try
Dim User As New UserRole(Me.SiteID, Master.UserName)
If User.GetLevel(Permissions.Edit) >= Levels.Page Then
Exit Sub
End If
Catch ex As Exception
End Try
Response.Redirect("/Manage/Errors/Unauthorized.aspx")
End Sub
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If Me.IsPostBack = True Then
Exit Sub
End If
Try
Dim Item As New PageBase(Me.PageID)
Me.txtCode.Text = Item.Code
Catch ex As Exception
Master.ShowError("Flex encountered a problem reading this page.")
End Try
End Sub
Private Sub cmbSnippet_SelectedIndexChanged(sender As Object, e As EventArgs) Handles cmbSnippet.SelectedIndexChanged
If Me.cmbSnippet.SelectedIndex = 0 Then
Exit Sub
End If
Try
Dim Filename As String = String.Format("/Manage/Editors/Text/Scripts/{0}", Me.cmbSnippet.SelectedValue)
Me.txtCode.Text = My.Computer.FileSystem.ReadAllText(Server.MapPath(Filename))
Exit Sub
Catch ex As Exception
End Try
Master.ShowError("Flex encountered a problem reading the snippet.")
End Sub
Private Sub btnOk_Click(sender As Object, e As EventArgs) Handles btnOk.Click
Try
Dim Item As New PageBase(Me.PageID)
Item.Code = Me.txtCode.Text
If Item.Update = True Then
Me.ShowUpdateTime()
Exit Sub
End If
Catch ex As Exception
End Try
Master.ShowError("Flex encountered a problem modifying this page.")
End Sub
Private Sub btnCancel_Click(sender As Object, e As EventArgs) Handles btnCancel.Click
Response.Redirect(String.Format("/Manage/Preview.aspx?PageID={0}", Me.PageID))
End Sub

Answer 1

This may or may not solve the issue.
.NET 4 and earlier don't know what IE 10 is. It's not in the list of browsers .NET knows about, so .NET assumes the browser is something that can't handle...well, anything really. Javascript and cookies, and I suspect more, get screwed over. So:
Download this: http://www.hanselman.com/blog/content/binary/App_BrowsersUpdate.zip, which is taken from here:
http://www.hanselman.com/blog/BugAndFixASPNETFailsToDetectIE10CausingDoPostBackIsUndefinedJavaScriptErrorOrMaintainFF5ScrollbarPosition.aspx,
which is referenced from here: IE10 User-Agent causes ASP.Net to not send back Set-Cookie (IE10 not setting cookies)
Extract the files and put them in your application's App_Browser directory. Rebuild and see if that works.