Hi, With the help of https://github.com/l0rdn1kk0n/wicket-clientside-logging we identified few problems where a component has been added to the AjaxRequestTarget for re-rendering but then wicket-ajax.js failed because it wasn't able to find the old html element with this markup id. The reason was that a parent component was set invisible.
I think we can add check in org.apache.wicket.ajax.XmlAjaxResponse#writeComponent that logs an ERROR/WARN when a component is not visible in hierarchy. This will be done only in DEV mode to not slow down the app. Any objections ? Ideas what else could be checked too ? Martin Grigorov Wicket Training and Consulting
