when I add a list without set the sitemap configuration,It will have a error when I click the tittle in the list<br><br><pre><pre>org.opencms.main.CmsRuntimeException: It's not possible to get the String value of a nested XML content definition.<br> at org.opencms.xml.types.CmsXmlNestedContentDefinition.getStringValue(CmsXmlNestedContentDefinition.java:140)<br> at org.opencms.xml.A_CmsXmlDocument.getStringValue(A_CmsXmlDocument.java:417)<br> at org.opencms.loader.A_CmsXmlDocumentLoader.dumpAsString(A_CmsXmlDocumentLoader.java:149)<br>    at org.opencms.loader.CmsXmlContentLoader.dumpAsString(CmsXmlContentLoader.java:52)<br>   at org.opencms.loader.A_CmsXmlDocumentLoader.service(A_CmsXmlDocumentLoader.java:245)<br> at org.opencms.loader.CmsXmlContentLoader.service(CmsXmlContentLoader.java:52)<br>        at org.opencms.flex.CmsFlexRequestDispatcher.includeInternalWithCache(CmsFlexRequestDispatcher.java:425)<br>      at org.opencms.flex.CmsFlexRequestDispatcher.include(CmsFlexRequestDispatcher.java:175)<br>       at org.opencms.jsp.CmsJspTagInclude.includeActionWithCache(CmsJspTagInclude.java:364)<br> at org.opencms.jsp.CmsJspTagInclude.includeTagAction(CmsJspTagInclude.java:240)<br>       at org.opencms.jsp.CmsJspTagInclude.doEndTag(CmsJspTagInclude.java:475)<br></pre></pre><br>