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The RadEditor field depends on loading of certain resources and scripts.
Could you please confirm that the Telerik.Web.UI.WebResource.axd script is loaded (Please see the attached screenshot). It will be very helpful, if you could please send us screenshots or information about all loaded scripts you can see in the console under Network->Scripts.
The described behaviour could also be caused by an add-on. Could you please provide us details of the add ons you use?
Thank you in advance.
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