Once setResponsePage is called the AjaxRequestTarget is pushed down in the list of request targets and AjaxRequestTarget won't be called anymore because AbstractRequestCycleProcessor.respond invokes the current request target only.
My page has some ajax links that delegates handling to different module and link does not know whether redirect happens. The link still has to update some components. But in case of redirect all the updates aren't applied and backbuttoning shows old state (actually with ajax indicator covering all the page so any element is not clickable). I believe it makes sence to defer switching to different request target until finishing responding on ajax request. https://issues.apache.org/jira/browse/WICKET-3010