"I receive the error when I place the control in the edittemplate of a Detailsview. The Detailsview is in VWS replaced with a box containing the errror. At runtime everything works well."

 

I am in the exact same situation!  I too like CuteEditor a lot and will be getting licensed.  And I have the same problem with using the editor in a template field of the DetailsView in an AJAX updatepanel.  It seems to work ok though and will continue using it unless something detrimental becomes evident with use.

 

I will be watching to see if any progress is made to resolve the issue.