EDIT

…und beim Logout:

com.vaadin.server.ServerRpcManager$RpcInvocationException: Unable to invoke method click in com.vaadin.shared.ui.button.ButtonServerRpc
               at com.vaadin.server.ServerRpcManager.applyInvocation(ServerRpcManager.java:162)
               at com.vaadin.server.ServerRpcManager.applyInvocation(ServerRpcManager.java:119)
               at com.vaadin.server.communication.ServerRpcHandler.handleInvocation(ServerRpcHandler.java:437)
               at com.vaadin.server.communication.ServerRpcHandler.handleInvocations(ServerRpcHandler.java:402)
               at com.vaadin.server.communication.ServerRpcHandler.handleRpc(ServerRpcHandler.java:273)
               at com.vaadin.server.communication.UidlRequestHandler.synchronizedHandleRequest(UidlRequestHandler.java:90)
               at com.vaadin.server.SynchronizedRequestHandler.handleRequest(SynchronizedRequestHandler.java:41)
               at com.vaadin.server.VaadinService.handleRequest(VaadinService.java:1436)
               at com.vaadin.server.VaadinServlet.service(VaadinServlet.java:380)
               at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
               at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:808)
               at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1669)
               at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:316)
               at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:126)
               at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:90)
               at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
               at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:114)
               at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
               at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:122)
               at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
               at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:111)
               at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
               at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:169)
               at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
               at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:48)
               at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
               at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilterInternal(BasicAuthenticationFilter.java:158)
               at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
               at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
               at org.springframework.security.oauth2.provider.authentication.OAuth2AuthenticationProcessingFilter.doFilter(OAuth2AuthenticationProcessingFilter.java:176)
               at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
               at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:120)
               at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
               at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:64)
               at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
               at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
               at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:91)
               at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
               at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:53)
               at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
               at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
               at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:213)
               at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:176)
               at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)
               at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:262)
               at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
               at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:121)
               at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
               at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
               at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:585)
               at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
               at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:577)
               at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:223)
               at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1127)
               at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:515)
               at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:185)
               at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1061)
               at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
               at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:215)
               at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:97)
               at org.eclipse.jetty.server.Server.handle(Server.java:497)
               at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:310)
               at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:257)
               at org.eclipse.jetty.io.AbstractConnection$2.run(AbstractConnection.java:540)
               at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:635)
               at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:555)
               at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.reflect.InvocationTargetException
               at sun.reflect.GeneratedMethodAccessor1962.invoke(Unknown Source)
               at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
               at java.lang.reflect.Method.invoke(Method.java:498)
               at com.vaadin.server.ServerRpcManager.applyInvocation(ServerRpcManager.java:158)
               ... 66 more
Caused by: com.vaadin.event.ListenerMethod$MethodException: Invocation of method buttonClick in eu.etaxonomy.cdm.vaadin.toolbar.RegistrationToolbar$$Lambda$51/1290793555 failed.
               at com.vaadin.event.ListenerMethod.receiveEvent(ListenerMethod.java:533)
               at com.vaadin.event.EventRouter.fireEvent(EventRouter.java:200)
               at com.vaadin.event.EventRouter.fireEvent(EventRouter.java:163)
               at com.vaadin.server.AbstractClientConnector.fireEvent(AbstractClientConnector.java:1015)
               at com.vaadin.ui.Button.fireClick(Button.java:377)
               at com.vaadin.ui.Button$1.click(Button.java:54)
               ... 70 more
Caused by: java.lang.NullPointerException
               at eu.etaxonomy.cdm.vaadin.view.registration.ListPresenter.loadFilterFromView(ListPresenter.java:272)
               at eu.etaxonomy.cdm.vaadin.view.registration.ListPresenter.preserveSearchFilterInSession(ListPresenter.java:251)
               at eu.etaxonomy.cdm.vaadin.view.registration.ListPresenter.onViewExit(ListPresenter.java:144)
               at eu.etaxonomy.vaadin.mvp.AbstractView.releaseResourcesOnAccessDenied(AbstractView.java:100)
               at eu.etaxonomy.cdm.vaadin.permission.AnnotationBasedAccessControlBean.isAccessGranted(AnnotationBasedAccessControlBean.java:66)
               at com.vaadin.spring.navigator.SpringViewProvider.isAccessGrantedToViewInstance(SpringViewProvider.java:515)
               at com.vaadin.spring.navigator.SpringViewProvider.getViewFromApplicationContextAndCheckAccess(SpringViewProvider.java:470)
               at com.vaadin.spring.navigator.SpringViewProvider.getViewFromApplicationContext(SpringViewProvider.java:443)
               at com.vaadin.spring.navigator.SpringViewProvider.getView(SpringViewProvider.java:405)
               at com.vaadin.navigator.Navigator.navigateTo(Navigator.java:558)
               at eu.etaxonomy.vaadin.ui.navigation.NavigationManagerBean.navigateTo(NavigationManagerBean.java:133)
               at eu.etaxonomy.vaadin.ui.navigation.NavigationManagerBean.reloadCurrentView(NavigationManagerBean.java:219)
               at eu.etaxonomy.cdm.vaadin.toolbar.RegistrationToolbar.performLogut(RegistrationToolbar.java:132)
               at eu.etaxonomy.cdm.vaadin.toolbar.RegistrationToolbar.lambda$initialize$61446b05$1(RegistrationToolbar.java:82)
               at sun.reflect.GeneratedMethodAccessor1963.invoke(Unknown Source)
               at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
               at java.lang.reflect.Method.invoke(Method.java:498)
               at com.vaadin.event.ListenerMethod.receiveEvent(ListenerMethod.java:510)
               ... 75 more