I’ve made a custom control based on the autocompletextender control in the AJAX control toolkit. The control lists registered users with name or email address containing the typed chars. This works fine on a test page. The challenge is to use it as a custom property in edit mode. The version I’m using for test is 4.61. The std approach with container.controls.add(xxx) in CreateChildControls does not work. It gives an error that reads appx “Extender controls cannot be registered before prerender”. My second attempt was to add a render delegate ; container.SetRenderMethodDelegate(this.Render); and then render my user control there. That gives the following error: The control with ID 'autoComplete1' requires a ScriptManager on the page. The ScriptManager must appear before any controls that need it. I have a script manager in the control so I suspect it has to do with proper initialization. Has anyone hit the same problems and solved them? Can we hope for EPiServer to come up with a white paper with all the ‘how to’ for using AJAX with EPiServer? Please!