Ajax Extensions referenced incorrectly in migrated project

Hi,

Please help. This is driving me nuts.

I migrated a web forms project from VS2008 .NET3.5 to VS2013 .Net3.5

I now find every time I edit the markup the designer.vb get's corrupted.

It get's changed from

    Protected WithEvents UpdatePanel1 As Global.Web.UI.UpdatePanel

to

    Protected WithEvents UpdatePanel1 As Global.AjaxControlToolkit.UpdatePanel

This does not happen on my colleague's machine when she edits the same file.

It also does not happen with all Ajax enabled projects on my machine

Here's a related post which seems unresolved

http://forums.asp.net/t/1870977.aspx?AJAX+Extensions+undefined+on+open+aspx+page+after+upgrade+to+VS2012+on+Win+7+64bit

Thanks

fid