Unfortunately it seems that this is unsupported scenario with the 'Prometheus' controls. We have logged it in our bug tracking system and will investigate it. We are not sure though, why you would need nested AjaxPanels. The parent one will take care of the ajaxification of all controls within it and the second one is not needed - can you elaborate on this? Your Telerik points have been updated for pointing this out.
To get this working you can use either of the following:
- remove the nested AjaxPanel
- use AjaxManager to ajaxify the controls
Looking forward to your reply.
the Telerik team