Commented Unassigned: Error - Collection was modified; enumeration operation may not execute. [27516]

There is discussion about this error @
http://forums.asp.net/p/1931886/5501172.aspx?p=True&t=635139958730585976&pagenum=1


StackTrace at System.ThrowHelper.ThrowInvalidOperationException(ExceptionResource resource)
at System.Collections.Generic.List`1.Enumerator.MoveNextRare()
at System.Collections.Generic.List`1.Enumerator.MoveNext()
at System.Linq.Enumerable.All[TSource](IEnumerable`1 source, Func`2 predicate)
at AjaxControlToolkit.ToolkitScriptManagerCombiner.GetScriptReferences(HttpContextBase context, String[] bundles)
at AjaxControlToolkit.ToolkitScriptManager.OnLoad(EventArgs e)
at System.Web.UI.Control.LoadRecursive()
at System.Web.UI.Control.LoadRecursive()
at System.Web.UI.Control.LoadRecursive()
at System.Web.UI.Control.LoadRecursive()
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)


It happens at random times at random pages on the site with or without any ajax controls (other than the toolkitscriptmanager on the master page).


Comments: From looking at the source code I think the problem is that ToolkitScriptManager has a static reference to ToolkitScriptManagerCombiner, but some of the methods in ToolkitScriptCombiner, including GetScriptReferences, are not thread-safe.