[REGRESSION] Show referring documents doesn't show dialog

in the quickstart

• create a link in article2 to article1
• go to article1
• show referring documents...
  -> Dialog doesn't show

In the logs:

03.12.2009 09:28:24 ERROR [org.apache.wicket.RequestCycle.logRuntimeException():1521] Unable to find the markup for the component. That may be due to transparent containers or components implementing IComponentResolver: [MarkupContainer [Component id = feedback]]
org.apache.wicket.WicketRuntimeException: Unable to find the markup for the component. That may be due to transparent containers or components implementing IComponentResolver: [MarkupContainer [Component id = feedback]]
at org.apache.wicket.MarkupFragmentFinder.find(MarkupFragmentFinder.java:125)
at org.apache.wicket.Component.locateMarkupStream(Component.java:3811)
at org.apache.wicket.Component.renderComponent(Component.java:2548)
at org.apache.wicket.ajax.AjaxRequestTarget.respondComponent(AjaxRequestTarget.java:827)
at org.apache.wicket.ajax.AjaxRequestTarget.respondComponents(AjaxRequestTarget.java:680)
at org.apache.wicket.ajax.AjaxRequestTarget.respond(AjaxRequestTarget.java:590)
at org.apache.wicket.request.AbstractRequestCycleProcessor.respond(AbstractRequestCycleProcessor.java:105)
at org.apache.wicket.RequestCycle.processEventsAndRespond(RequestCycle.java:1258)
at org.apache.wicket.RequestCycle.step(RequestCycle.java:1329)
at org.apache.wicket.RequestCycle.steps(RequestCycle.java:1428)
at org.apache.wicket.RequestCycle.request(RequestCycle.java:545)
at org.apache.wicket.protocol.http.WicketFilter.doGet(WicketFilter.java:468)
at org.apache.wicket.protocol.http.WicketFilter.doFilter(WicketFilter.java:301)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1115)
at org.hippoecm.frontend.plugins.login.ConcurrentLoginFilter.doFilter(ConcurrentLoginFilter.java:54)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1115)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:361)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:766)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:417)
at org.mortbay.jetty.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:230)
at org.mortbay.jetty.handler.HandlerCollection.handle(HandlerCollection.java:114)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:324)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:534)
at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:864)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:533)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:207)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:403)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409)
at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:522)