. If you can reproduce such a problem with our online demos can you show us the exact steps so we can investigate the case?
Back to your question - in order to answer it we would need more information on what is the relation between the server-side events you have and the RadEditor managers, i.e. are you attempting to modify them in the server code, are you trying to invoke them from the server or something else entirely? The control has no server-side events on its own and any extensions you have made in this regard are not supported is the likely answer based on the provided information.
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