Backport 7.6: Xinha editor autosave causes WicketAjax to block

When upgrading our 7.7.6 project to use CMS 2.22.11 (and related versions of channel-manager, hst and packages) the Xinha editor stops functioning and hangs the browser app. After a refresh it works fine but all changes are gone.
I tried it on a clean installation using the archetype, which initially gave me the same results, after a clean install. The next time I ran the project, it worked fine. After some time I get a log entry after saving the document:
[INFO] [talledLocalContainer] 25.09.2012 12:15:28 ERROR [org.apache.wicket.RequestCycle.logRuntimeException():1531] org.apache.wicket.WicketRuntimeException: component root:tabs:panel-container:cards:2:panel:center:tabs:panel-container:cards:2:panel:editor:extension.editor:form:template:view:4:item:view:1:item:fragment:value not found on page org.hippoecm.frontend.PluginPage[id = 1], listener interface = [RequestListenerInterface name=IActivePageBehaviorListener, method=public abstract void org.apache.wicket.behavior.IBehaviorListener.onRequest()]
[INFO] [talledLocalContainer] org.apache.wicket.protocol.http.request.InvalidUrlException: org.apache.wicket.WicketRuntimeException: component root:tabs:panel-container:cards:2:panel:center:tabs:panel-container:cards:2:panel:editor:extension.editor:form:template:view:4:item:view:1:item:fragment:value not found on page org.hippoecm.frontend.PluginPage[id = 1], listener interface = [RequestListenerInterface name=IActivePageBehaviorListener, method=public abstract void org.apache.wicket.behavior.IBehaviorListener.onRequest()]
[INFO] [talledLocalContainer] at org.apache.wicket.protocol.http.WebRequestCycleProcessor.resolve(WebRequestCycleProcessor.java:262)
[INFO] [talledLocalContainer] at org.apache.wicket.RequestCycle.step(RequestCycle.java:1312)
[INFO] [talledLocalContainer] at org.apache.wicket.RequestCycle.steps(RequestCycle.java:1438)
[INFO] [talledLocalContainer] at org.apache.wicket.RequestCycle.request(RequestCycle.java:546)
[INFO] [talledLocalContainer] at org.apache.wicket.protocol.http.WicketFilter.doGet(WicketFilter.java:486)
[INFO] [talledLocalContainer] at org.apache.wicket.protocol.http.WicketFilter.doFilter(WicketFilter.java:319)
[INFO] [talledLocalContainer] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
[INFO] [talledLocalContainer] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
[INFO] [talledLocalContainer] at org.hippoecm.frontend.ResourceRewriteFilter.doFilter(ResourceRewriteFilter.java:129)
[INFO] [talledLocalContainer] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
[INFO] [talledLocalContainer] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
[INFO] [talledLocalContainer] at org.hippoecm.frontend.plugins.login.ConcurrentLoginFilter.doFilter(ConcurrentLoginFilter.java:56)
[INFO] [talledLocalContainer] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
[INFO] [talledLocalContainer] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
[INFO] [talledLocalContainer] at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
[INFO] [talledLocalContainer] at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
[INFO] [talledLocalContainer] at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
[INFO] [talledLocalContainer] at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
[INFO] [talledLocalContainer] at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:615)
[INFO] [talledLocalContainer] at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
[INFO] [talledLocalContainer] at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
[INFO] [talledLocalContainer] at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859)
[INFO] [talledLocalContainer] at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:602)
[INFO] [talledLocalContainer] at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
[INFO] [talledLocalContainer] at java.lang.Thread.run(Thread.java:662)
[INFO] [talledLocalContainer] Caused by: org.apache.wicket.WicketRuntimeException: component root:tabs:panel-container:cards:2:panel:center:tabs:panel-container:cards:2:panel:editor:extension.editor:form:template:view:4:item:view:1:item:fragment:value not found on page org.hippoecm.frontend.PluginPage[id = 1], listener interface = [RequestListenerInterface name=IActivePageBehaviorListener, method=public abstract void org.apache.wicket.behavior.IBehaviorListener.onRequest()]
[INFO] [talledLocalContainer] at org.apache.wicket.request.AbstractRequestCycleProcessor.resolveListenerInterfaceTarget(AbstractRequestCycleProcessor.java:427)
[INFO] [talledLocalContainer] at org.apache.wicket.request.AbstractRequestCycleProcessor.resolveRenderedPage(AbstractRequestCycleProcessor.java:472)
[INFO] [talledLocalContainer] at org.apache.wicket.protocol.http.WebRequestCycleProcessor.resolve(WebRequestCycleProcessor.java:144)
[INFO] [talledLocalContainer] ... 24 more

When using this fix in combination with content blocks (as described in CMS7-6438) this issue happens more often and unfortunately under unpredictable circumstances.

We needed this update to resolve issue CMS7-6438 which was already blocking for us. At the moment I have no choice to downgrade back to the original 7.7.6 release.