In testing the showcase-portlet examples on Liferay (version 5.2.3 only, not on versions 6.0 or 6.1), the following behaviour was observed. It exists in the EE-3.0.0.GA release as well as on the current maintenance branch.

When running any of the File Entry examples, after selecting a file and clicking the "Send File" button, the operation fails and the following exception is thrown:

Sep 5, 2012 9:06:16 PM org.icefaces.impl.application.ExtendedExceptionHandler handle
WARNING: queued exception
java.lang.IllegalArgumentException: null source
at java.util.EventObject.<init>(EventObject.java:38)
at javax.faces.event.SystemEvent.<init>(SystemEvent.java:71)
at javax.faces.event.ComponentSystemEvent.<init>(ComponentSystemEvent.java:73)
at javax.faces.event.PostRestoreStateEvent.<init>(PostRestoreStateEvent.java:73)
at com.sun.faces.lifecycle.RestoreViewPhase.deliverPostRestoreStateEvent(RestoreViewPhase.java:271)
at com.sun.faces.lifecycle.RestoreViewPhase.execute(RestoreViewPhase.java:257)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.RestoreViewPhase.doPhase(RestoreViewPhase.java:116)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118)
at org.portletfaces.bridge.BridgeImpl.doFacesRequest(BridgeImpl.java:524)
at org.portletfaces.bridge.GenericFacesPortlet.serveResource(GenericFacesPortlet.java:131)
at com.sun.portal.portletcontainer.appengine.filter.FilterChainImpl.doFilter(FilterChainImpl.java:177)
at com.liferay.portal.kernel.portlet.PortletFilterUtil.doFilter(PortletFilterUtil.java:76)
at com.liferay.portal.kernel.servlet.PortletServlet.service(PortletServlet.java:100)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)