Hi Saffy,

What's the version of ajax control toolkit you are using?

And there are also have different version for .net 4.0 and .net 3.5.

You could refer to link below to download the ajax control toolkit for the different version of .net:

https://ajaxcontroltoolkit.codeplex.com/releases/view/116091

saffy

but when we host to server it display noting.

Could you find the editor in F12?

According to links below, the Editor and ToolkitScriptManger are deprecated :

https://github.com/DevExpress/AjaxControlToolkit/pull/71

https://ajaxcontroltoolkit.codeplex.com/wikipage?title=ToolkitScriptManager%20Removed%20in%20v15.1%2C%20Use%20ScriptManager

I think you could try to use HtmlEditorExtender for instead:

https://ajaxcontroltoolkit.devexpress.com/HtmlEditorExtender/HtmlEditorExtender.aspx

Best Regards

Billy