I am sorry, but I am not sure if I understand correctly your question.
1. SingleNews is obsolete and is not compiled in Telerik.New.dll anymore. Therefore, you cannot add it manually in the toolbox through web.config.
2. What exactly are you trying to achieve with the NewsView? What kind of customization do you want to make?
3. When editing a news view control, switch to Advanced tab, expand QueryString Keys, set
TagItemKey , CategoryKey and ContentItemKey are different for all NewsView controls on that page.
All the best,
the Telerik team
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