Steps to Reproduce: * Start the portal and go to e.g. _Home Page_ (the layout has to contain the _Navigation Portlet_).
* Sign in as _root_.
* Go to _Site Editor_ > _Edit Layout_.
* Click the _Switch View Mode_ button in the composer.
project_key: JBEPP

If you switch the view mode while editing the layout of a site with _Navigation Portlet_, the navigation is not loaded - the _Navigation Portlet_ isn't showing any nodes and the following exception is logged:

{code}
01:58:45,709 ERROR [PortletApplicationController] Error while rendering the porlet
org.exoplatform.groovyscript.TemplateRuntimeException: Groovy template exception at DataText[pos=Position[col=1,line=83],data=          def rootNodes = uicomponent.getNavigations();] for template app:/groovy/portal/webui/component/UIPortalNavigation.gtmpl
        at org.exoplatform.groovyscript.GroovyScript.buildRuntimeException(GroovyScript.java:178)
        at org.exoplatform.groovyscript.GroovyScript.render(GroovyScript.java:121)
        at org.exoplatform.groovyscript.GroovyTemplate.render(GroovyTemplate.java:118)
        at org.exoplatform.groovyscript.text.TemplateService.merge(TemplateService.java:117)
        at org.exoplatform.webui.core.lifecycle.Lifecycle.renderTemplate(Lifecycle.java:128)
        at org.exoplatform.webui.core.lifecycle.Lifecycle.processRender(Lifecycle.java:85)
        at org.exoplatform.webui.core.UIComponent.processRender(UIComponent.java:144)
        at org.exoplatform.webui.core.UIContainer.renderChildren(UIContainer.java:368)
        at org.exoplatform.webui.core.UIPortletApplication.renderChildren(UIPortletApplication.java:90)
        at org.exoplatform.webui.core.lifecycle.UIApplicationLifecycle.processRender(UIApplicationLifecycle.java:73)
        at org.exoplatform.webui.core.lifecycle.UIApplicationLifecycle.processRender(UIApplicationLifecycle.java:31)
        at org.exoplatform.webui.core.UIComponent.processRender(UIComponent.java:144)
        at org.exoplatform.webui.core.UIPortletApplication.processRender(UIPortletApplication.java:135)
        at org.exoplatform.webui.application.portlet.PortletApplication.render(PortletApplication.java:299)
        at org.exoplatform.webui.application.portlet.PortletApplicationController.render(PortletApplicationController.java:131)
        at org.gatein.pc.portlet.impl.jsr168.PortletContainerImpl$Invoker.doFilter(PortletContainerImpl.java:569)
        at org.gatein.pc.portlet.impl.jsr168.api.FilterChainImpl.doFilter(FilterChainImpl.java:159)
        at org.exoplatform.portal.application.ApplicationMonitoringFilter.doFilter(ApplicationMonitoringFilter.java:77)
        at org.gatein.pc.portlet.impl.jsr168.api.FilterChainImpl.doFilter(FilterChainImpl.java:159)
        at org.gatein.pc.portlet.impl.jsr168.api.FilterChainImpl.doFilter(FilterChainImpl.java:80)
        at org.gatein.pc.portlet.impl.jsr168.PortletContainerImpl.dispatch(PortletContainerImpl.java:506)
        at org.gatein.pc.portlet.container.ContainerPortletDispatcher.invoke(ContainerPortletDispatcher.java:42)
        at org.gatein.pc.portlet.PortletInvokerInterceptor.invoke(PortletInvokerInterceptor.java:93)
        at org.gatein.pc.portlet.aspects.EventPayloadInterceptor.invoke(EventPayloadInterceptor.java:197)
        at org.gatein.pc.portlet.PortletInvokerInterceptor.invoke(PortletInvokerInterceptor.java:93)
        at org.gatein.wsrp.payload.WSRPEventPayloadInterceptor.invoke(WSRPEventPayloadInterceptor.java:153)
        at org.gatein.pc.portlet.PortletInvokerInterceptor.invoke(PortletInvokerInterceptor.java:93)
        at org.gatein.pc.portlet.aspects.RequestAttributeConversationInterceptor.invoke(RequestAttributeConversationInterceptor.java:119)
        at org.gatein.pc.portlet.PortletInvokerInterceptor.invoke(PortletInvokerInterceptor.java:93)
        at org.gatein.pc.portlet.aspects.CCPPInterceptor.invoke(CCPPInterceptor.java:65)
        at org.gatein.pc.portlet.PortletInvokerInterceptor.invoke(PortletInvokerInterceptor.java:93)
        at org.gatein.pc.bridge.BridgeInterceptor.invoke(BridgeInterceptor.java:49)
        at org.gatein.pc.portlet.PortletInvokerInterceptor.invoke(PortletInvokerInterceptor.java:93)
        at org.gatein.pc.portlet.PortletInvokerInterceptor.invoke(PortletInvokerInterceptor.java:93)
        at org.gatein.pc.portlet.aspects.SessionInvalidatorInterceptor.invoke(SessionInvalidatorInterceptor.java:55)
        at org.gatein.pc.portlet.PortletInvokerInterceptor.invoke(PortletInvokerInterceptor.java:93)
        at org.gatein.pc.portlet.aspects.ContextDispatcherInterceptor.access$001(ContextDispatcherInterceptor.java:49)
        at org.gatein.pc.portlet.aspects.ContextDispatcherInterceptor$1.doCallback(ContextDispatcherInterceptor.java:123)
        at org.gatein.wci.command.CommandDispatcher$CallbackCommand.execute(CommandDispatcher.java:82)
        at sun.reflect.GeneratedMethodAccessor470.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at org.gatein.wci.command.CommandServlet.doGet(CommandServlet.java:135)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:638)
        at org.apache.catalina.core.ApplicationDispatcher.doInclude(ApplicationDispatcher.java:543)
        at org.apache.catalina.core.ApplicationDispatcher.include(ApplicationDispatcher.java:480)
        at org.gatein.wci.command.CommandServlet.include(CommandServlet.java:84)
        at org.gatein.wci.command.CommandDispatcher.include(CommandDispatcher.java:58)
        at org.gatein.wci.tomcat.TC6ServletContainerContext.include(TC6ServletContainerContext.java:99)
        at org.gatein.wci.impl.DefaultServletContainer.include(DefaultServletContainer.java:271)
        at org.gatein.pc.portlet.impl.spi.AbstractServerContext.dispatch(AbstractServerContext.java:69)
        at org.gatein.pc.portlet.aspects.ContextDispatcherInterceptor.invoke(ContextDispatcherInterceptor.java:77)
        at org.gatein.pc.portlet.PortletInvokerInterceptor.invoke(PortletInvokerInterceptor.java:93)
        at org.gatein.pc.portlet.aspects.SecureTransportInterceptor.invoke(SecureTransportInterceptor.java:69)
        at org.gatein.pc.portlet.PortletInvokerInterceptor.invoke(PortletInvokerInterceptor.java:93)
        at org.gatein.pc.portlet.aspects.ValveInterceptor.invoke(ValveInterceptor.java:75)
        at org.gatein.pc.portlet.PortletInvokerInterceptor.invoke(PortletInvokerInterceptor.java:93)
        at org.gatein.pc.portlet.container.ContainerPortletInvoker.invoke(ContainerPortletInvoker.java:131)
        at org.gatein.pc.portlet.PortletInvokerInterceptor.invoke(PortletInvokerInterceptor.java:93)
        at org.gatein.pc.portlet.state.producer.ProducerPortletInvoker.invoke(ProducerPortletInvoker.java:249)
        at org.gatein.pc.federation.impl.FederatedPortletInvokerService.invoke(FederatedPortletInvokerService.java:163)
        at org.gatein.pc.federation.impl.FederatingPortletInvokerService.invoke(FederatingPortletInvokerService.java:244)
        at org.gatein.pc.portlet.PortletInvokerInterceptor.invoke(PortletInvokerInterceptor.java:93)
        at org.gatein.pc.portlet.aspects.PortletCustomizationInterceptor.invoke(PortletCustomizationInterceptor.java:76)
        at org.gatein.pc.portlet.PortletInvokerInterceptor.invoke(PortletInvokerInterceptor.java:93)
        at org.gatein.pc.portlet.aspects.ConsumerCacheInterceptor.invoke(ConsumerCacheInterceptor.java:165)
        at org.gatein.pc.portlet.PortletInvokerInterceptor.invoke(PortletInvokerInterceptor.java:93)
        at org.exoplatform.portal.webui.application.UIPortlet.invoke(UIPortlet.java:1041)
        at org.exoplatform.portal.webui.application.UIPortletLifecycle.processRender(UIPortletLifecycle.java:203)
        at org.exoplatform.portal.webui.application.UIPortletLifecycle.processRender(UIPortletLifecycle.java:62)
        at org.exoplatform.webui.core.UIComponent.processRender(UIComponent.java:144)
        at org.exoplatform.webui.core.UIContainer.renderChildren(UIContainer.java:368)
        at org.exoplatform.webui.core.UIContainer.renderChildren(UIContainer.java:358)
        at sun.reflect.GeneratedMethodAccessor477.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite$PojoCachedMethodSiteNoUnwrapNoCoerce.invoke(PojoMetaMethodSite.java:229)
        at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite.call(PojoMetaMethodSite.java:52)
        at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:120)
        at UIPortal.run(UIPortal.gtmpl:18)
        at org.exoplatform.groovyscript.GroovyScript.render(GroovyScript.java:111)
        at org.exoplatform.groovyscript.GroovyTemplate.render(GroovyTemplate.java:118)
        at org.exoplatform.groovyscript.text.TemplateService.merge(TemplateService.java:117)
        at org.exoplatform.webui.core.lifecycle.Lifecycle.renderTemplate(Lifecycle.java:128)
        at org.exoplatform.webui.core.lifecycle.Lifecycle.processRender(Lifecycle.java:85)
        at org.exoplatform.portal.webui.portal.UIPortalLifecycle.processRender(UIPortalLifecycle.java:41)
        at org.exoplatform.portal.webui.portal.UIPortalLifecycle.processRender(UIPortalLifecycle.java:30)
        at org.exoplatform.webui.core.UIComponent.processRender(UIComponent.java:144)
        at org.exoplatform.webui.core.UIComponentDecorator.renderChildren(UIComponentDecorator.java:101)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite$PojoCachedMethodSiteNoUnwrapNoCoerce.invoke(PojoMetaMethodSite.java:229)
        at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite.call(PojoMetaMethodSite.java:52)
        at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:120)
        at UIPortalToolPanel.run(UIPortalToolPanel.gtmpl:2)
        at org.exoplatform.groovyscript.GroovyScript.render(GroovyScript.java:111)
        at org.exoplatform.groovyscript.GroovyTemplate.render(GroovyTemplate.java:118)
        at org.exoplatform.groovyscript.text.TemplateService.merge(TemplateService.java:117)
        at org.exoplatform.webui.core.lifecycle.Lifecycle.renderTemplate(Lifecycle.java:128)
        at org.exoplatform.webui.core.lifecycle.Lifecycle.processRender(Lifecycle.java:85)
        at org.exoplatform.webui.core.UIComponent.processRender(UIComponent.java:144)
        at org.exoplatform.portal.webui.workspace.UIPortalToolPanel.processRender(UIPortalToolPanel.java:58)
        at org.exoplatform.webui.core.UIApplication.renderBlockToUpdate(UIApplication.java:151)
        at org.exoplatform.portal.webui.workspace.UIPortalApplication.processRender(UIPortalApplication.java:657)
        at org.exoplatform.portal.application.PortalRequestHandler.processRequest(PortalRequestHandler.java:184)
        at org.exoplatform.portal.application.PortalRequestHandler.execute(PortalRequestHandler.java:150)
        at org.exoplatform.web.WebAppController.service(WebAppController.java:349)
        at org.exoplatform.portal.application.PortalController.onService(PortalController.java:127)
        at org.exoplatform.container.web.AbstractHttpServlet.service(AbstractHttpServlet.java:132)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.exoplatform.web.login.RememberMeFilter.doFilter(RememberMeFilter.java:86)
        at org.exoplatform.web.login.RememberMeFilter.doFilter(RememberMeFilter.java:54)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.exoplatform.web.filter.ExtensibleFilter$ExtensibleFilterChain.doFilter(ExtensibleFilter.java:112)
        at org.exoplatform.web.filter.ExtensibleFilter.doFilter(ExtensibleFilter.java:84)
        at org.exoplatform.web.filter.GenericFilter.doFilter(GenericFilter.java:66)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.exoplatform.web.CacheUserProfileFilter.doFilter(CacheUserProfileFilter.java:73)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.exoplatform.frameworks.jcr.web.ThreadLocalSessionProviderInitializedFilter.doFilter(ThreadLocalSessionProviderInitializedFilter.java:116)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.exoplatform.services.security.web.SetCurrentIdentityFilter.doFilter(SetCurrentIdentityFilter.java:88)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.exoplatform.portal.application.localization.LocalizationFilter.doFilter(LocalizationFilter.java:179)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.exoplatform.web.login.ClusteredSSOFilter.doFilter(ClusteredSSOFilter.java:73)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.exoplatform.container.web.PortalContainerFilter.doFilter(PortalContainerFilter.java:69)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.exoplatform.container.web.PortalContainerFilter.doFilter(PortalContainerFilter.java:69)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:235)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
        at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:183)
        at org.jboss.web.tomcat.service.session.ClusteredSessionValve.handleRequest(ClusteredSessionValve.java:135)
        at org.jboss.web.tomcat.service.session.ClusteredSessionValve.invoke(ClusteredSessionValve.java:94)
        at org.jboss.web.tomcat.service.session.LockingValve.invoke(LockingValve.java:62)
        at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:433)
        at org.exoplatform.web.login.PortalClusteredSSOSupportValve.invoke(PortalClusteredSSOSupportValve.java:120)
        at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:95)
        at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.process(SecurityContextEstablishmentValve.java:126)
        at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.invoke(SecurityContextEstablishmentValve.java:70)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
        at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:158)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:330)
        at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:829)
        at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:599)
        at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:451)
        at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.NullPointerException
        at org.exoplatform.portal.webui.portal.UIPortal.getUserNavigation(UIPortal.java:218)
        at org.exoplatform.portal.webui.navigation.UIPortalNavigation.getCurrentNavigation(UIPortalNavigation.java:300)
        at org.exoplatform.portal.webui.navigation.UIPortalNavigation.getNavigations(UIPortalNavigation.java:125)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite$PojoCachedMethodSiteNoUnwrapNoCoerce.invoke(PojoMetaMethodSite.java:229)
        at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite.call(PojoMetaMethodSite.java:52)
        at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:120)
        at UIPortalNavigation.run(UIPortalNavigation.gtmpl:83)
        at org.exoplatform.groovyscript.GroovyScript.render(GroovyScript.java:111)
        ... 169 more
{code}

Note: This is technically a regression (works fine with 5.1.1.GA).