Commented Unassigned: AjaxControlToolkit.Sanitizer is not working with HtmlAgilityPack 1.4.6 [27403]

I am using HtmlAgilityPackSanitizerProvider in my asp.net 4.5 website application.

I want to use latest HtmlAgilityPack 1.4.6 but the asp.net ajax control toolkit SanitizerProviders giving me error below

how can i fix that ?

Could not load file or assembly 'HtmlAgilityPack, Version=1.4.0.0, Culture=neutral, PublicKeyToken=bd319b19eaf3b43a' or one of its dependencies.

http://i.stack.imgur.com/S5kFF.png
Comments: Got rid of the HtmlAgilityPack 1.4.6 pack and it is now working with my HtmlEditorExtender. Does it mean the HtmlAgilityPack is not required with this version?