java.lang.IllegalArgumentException: ancestor == descendant!!!
   at org.netbeans.modules.editor.structure.api.DocumentModel.isDescendantOf(DocumentModel.java:322)
   at org.netbeans.modules.editor.structure.api.DocumentModel.getChildren(DocumentModel.java:635)
   at org.netbeans.modules.editor.structure.api.DocumentElement.getChildren(DocumentElement.java:299)
   at org.netbeans.modules.xml.text.structure.XMLDocumentModelProvider.getDescendantsOfNotSkippedElements(XMLDocumentModelProvider.java:474)
   at org.netbeans.modules.xml.text.structure.XMLDocumentModelProvider.generateDocumentElements(XMLDocumentModelProvider.java:452)
   at org.netbeans.modules.xml.text.structure.XMLDocumentModelProvider.updateModel(XMLDocumentModelProvider.java:266)
   at org.netbeans.modules.editor.structure.api.DocumentModel.updateModel(DocumentModel.java:512)
   at org.netbeans.modules.editor.structure.api.DocumentModel.access$000(DocumentModel.java:128)
   at org.netbeans.modules.editor.structure.api.DocumentModel$1.run(DocumentModel.java:191)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1423)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2033)