After update jsf1.2 to jsf-1.2_07-b03-FCS ( with recompiling icefaces sources)
 I see some strange behavior for complex xtml pages.

Some pages got error with no details.

5:55:41,694 ERROR D2DFaceletViewHandler: Problem in renderResponse: null
java.lang.UnsupportedOperationException
at com.icesoft.faces.context.BridgeFacesContext.getMaximumSeverity(BridgeFacesContext.java:143)
at javax.faces.component.UIData.contextHasErrorMessages(UIData.java:1313)
at javax.faces.component.UIData.keepSaved(UIData.java:1287)
at javax.faces.component.UIData.encodeBegin(UIData.java:946)
at com.icesoft.faces.component.panelseries.UISeries.encodeBegin(UISeries.java:249)
at com.icesoft.faces.renderkit.dom_html_basic.DomBasicRenderer.encodeParentAndChildren(DomBasicRenderer.java:350)
at com.icesoft.faces.renderkit.dom_html_basic.GroupRenderer.encodeChildren(GroupRenderer.java:92)
at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:826)
at com.icesoft.faces.application.D2DViewHandler.renderResponse(D2DViewHandler.java:539)
at com.icesoft.faces.application.D2DViewHandler.renderResponse(D2DViewHandler.java:543)
at com.icesoft.faces.application.D2DViewHandler.renderResponse(D2DViewHandler.java:543)
at com.icesoft.faces.application.D2DViewHandler.renderResponse(D2DViewHandler.java:543)
at com.icesoft.faces.application.D2DViewHandler.renderResponse(D2DViewHandler.java:543)
at com.icesoft.faces.facelets.D2DFaceletViewHandler.renderResponse(D2DFaceletViewHandler.java:286)
at com.icesoft.faces.application.D2DViewHandler.renderView(D2DViewHandler.java:161)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:110)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:100)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139)
at com.icesoft.faces.webapp.http.core.JsfLifecycleExecutor.apply(JsfLifecycleExecutor.java:18)
at com.icesoft.faces.webapp.http.core.PageServer$1.respond(PageServer.java:25)
at com.icesoft.faces.webapp.http.servlet.ServletRequestResponse.respondWith(ServletRequestResponse.java:162)
at com.icesoft.faces.webapp.http.servlet.ContinuationAdaptingServlet$ContinuationRequestResponse.respondWith(ContinuationAdaptingServlet.java:47)
at com.icesoft.faces.webapp.http.core.PageServer.service(PageServer.java:30)
at com.icesoft.faces.webapp.http.core.SingleViewServer.service(SingleViewServer.java:48)
at com.icesoft.faces.webapp.http.common.standard.PathDispatcherServer$Matcher.serviceOnMatch(PathDispatcherServer.java:50)
at com.icesoft.faces.webapp.http.common.standard.PathDispatcherServer.service(PathDispatcherServer.java:19)
at com.icesoft.faces.webapp.http.servlet.ContinuationAdaptingServlet.service(ContinuationAdaptingServlet.java:27)
at com.icesoft.faces.webapp.http.servlet.EnvironmentAdaptingServlet.service(EnvironmentAdaptingServlet.java:29)
at com.icesoft.faces.webapp.http.servlet.MainSessionBoundServlet.service(MainSessionBoundServlet.java:105)
at com.icesoft.faces.webapp.http.servlet.SessionDispatcher.service(SessionDispatcher.java:37)
at com.icesoft.faces.webapp.http.servlet.PathDispatcher$Matcher.serviceOnMatch(PathDispatcher.java:52)
at com.icesoft.faces.webapp.http.servlet.PathDispatcher.service(PathDispatcher.java:29)
at com.icesoft.faces.webapp.http.servlet.MainServlet.service(MainServlet.java:76)