java.lang.IllegalArgumentException: Comparison method violates its general contract!
   at java.util.TimSort.mergeLo(TimSort.java:747)
   at java.util.TimSort.mergeAt(TimSort.java:483)
   at java.util.TimSort.mergeCollapse(TimSort.java:408)
   at java.util.TimSort.sort(TimSort.java:214)
   at java.util.Arrays.sort(Arrays.java:727)
   at org.netbeans.modules.editor.structure.api.DocumentModel$ElementsArray.resort(DocumentModel.java:1430)
   at org.netbeans.modules.editor.structure.api.DocumentModel.checkDocumentDirty(DocumentModel.java:560)
   at org.netbeans.modules.editor.structure.api.DocumentModel.getLeafElementForOffset(DocumentModel.java:354)
   at org.netbeans.modules.xml.text.structure.XMLDocumentModelProvider.updateModel(XMLDocumentModelProvider.java:108)
   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$1.run(DocumentModel.java:191)
Caused: org.openide.util.RequestProcessor$SlowItem: task failed due to: java.lang.IllegalArgumentException: Comparison method violates its general contract!
   at org.openide.util.RequestProcessor$Task.schedule(RequestProcessor.java:1484)
   at org.netbeans.modules.editor.structure.api.DocumentModel.requestModelUpdate(DocumentModel.java:499)
   at org.netbeans.modules.editor.structure.api.DocumentModel.access$2100(DocumentModel.java:128)
   at org.netbeans.modules.editor.structure.api.DocumentModel$DocumentChangesWatcher.documentChanged(DocumentModel.java:1267)
   at org.netbeans.modules.editor.structure.api.DocumentModel$DocumentChangesWatcher.insertUpdate(DocumentModel.java:1231)
   at org.openide.util.WeakListenerImpl$Document.insertUpdate(WeakListenerImpl.java:298)
   at org.netbeans.lib.editor.util.swing.PriorityDocumentListenerList.insertUpdate(PriorityDocumentListenerList.java:85)
   at javax.swing.text.AbstractDocument.fireInsertUpdate(AbstractDocument.java:202)
   at org.netbeans.editor.BaseDocument.fireInsertUpdate(BaseDocument.java:1619)
   at org.netbeans.editor.BaseDocument.handleInsertString(BaseDocument.java:823)
   at org.netbeans.editor.BaseDocument.insertString(BaseDocument.java:751)
   at org.netbeans.editor.BaseDocument.read(BaseDocument.java:1447)
   at org.netbeans.editor.BaseKit.read(BaseKit.java:668)
   at org.openide.text.DataEditorSupport.loadFromStreamToKit(DataEditorSupport.java:491)
   at org.openide.text.DocumentOpenClose$DocumentLoad.atomicLockedRun(DocumentOpenClose.java:762)
   at org.openide.text.DocumentOpenClose$DocumentLoad.run(DocumentOpenClose.java:613)
   at org.netbeans.editor.GuardedDocument.runAtomic(GuardedDocument.java:323)
   at org.openide.text.NbDocument.runAtomic(NbDocument.java:436)
   at org.openide.text.DocumentOpenClose$DocumentLoad.run(DocumentOpenClose.java:653)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1443)
   at org.netbeans.modules.openide.util.GlobalLookup.execute(GlobalLookup.java:68)
   at org.openide.util.lookup.Lookups.executeWith(Lookups.java:303)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2058)