Created Issue: Mutli AjaxControlToolkit don't work on the same page [27348]

Hi,

I m using multi AjaxControlToolkit to uplaod images on the same page.

I was surprise to see the bad event handler was raise !

I have inspect the source code and I found the issue (I think)

The property ContextKeys is never used because the const contextKey is always used.

I think the constant sould be used only is ContextKeys is null or empty. Moreover I think the property should be named 'ContextKey'.