java.lang.NoSuchMethodError: org.netbeans.editor.ext.html.parser.SyntaxElement.type()I
   at org.netbeans.modules.html.validation.ValidatorImpl.containsHeadElement(ValidatorImpl.java:173)
   at org.netbeans.modules.html.validation.ValidatorImpl.filterCodeFragmentProblems(ValidatorImpl.java:158)
   at org.netbeans.modules.html.validation.ValidatorImpl.validate(ValidatorImpl.java:114)
   at org.netbeans.modules.html.editor.api.gsf.HtmlParserResult.getValidationResults(HtmlParserResult.java:240)
   at org.netbeans.modules.html.editor.api.gsf.HtmlParserResult.getDiagnostics(HtmlParserResult.java:217)
   at org.netbeans.modules.html.editor.hints.HtmlRuleContext.<init>(HtmlRuleContext.java:68)
   at org.netbeans.modules.html.editor.hints.HtmlHintsProvider.computeErrors(HtmlHintsProvider.java:198)
   at org.netbeans.modules.html.editor.HtmlErrorFilter.filter(HtmlErrorFilter.java:96)
   at org.netbeans.modules.csl.core.ErrorFilterQuery.getFilteredErrors(ErrorFilterQuery.java:67)
   at org.netbeans.modules.csl.core.TLIndexerFactory$TLIndexer.index(TLIndexerFactory.java:241)
   at org.netbeans.modules.parsing.spi.indexing.Indexable$MyAccessor$3.run(Indexable.java:216)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater.runIndexer(RepositoryUpdater.java:253)
   at org.netbeans.modules.parsing.spi.indexing.Indexable$MyAccessor.index(Indexable.java:214)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work$3.run(RepositoryUpdater.java:2717)
   at org.netbeans.modules.parsing.impl.TaskProcessor.callUserTask(TaskProcessor.java:583)
   at org.netbeans.modules.parsing.api.ParserManager$UserTaskAction.run(ParserManager.java:150)
   at org.netbeans.modules.parsing.api.ParserManager$UserTaskAction.run(ParserManager.java:134)
   at org.netbeans.modules.parsing.impl.TaskProcessor$2.call(TaskProcessor.java:200)
   at org.netbeans.modules.parsing.impl.TaskProcessor$2.call(TaskProcessor.java:197)
   at org.netbeans.modules.masterfs.filebasedfs.utils.FileChangedManager.priorityIO(FileChangedManager.java:168)
   at org.netbeans.modules.masterfs.providers.ProvidedExtensions.priorityIO(ProvidedExtensions.java:360)
   at org.netbeans.modules.parsing.impl.Utilities.runPriorityIO(Utilities.java:72)
   at org.netbeans.modules.parsing.impl.TaskProcessor.runUserTask(TaskProcessor.java:197)
   at org.netbeans.modules.parsing.api.ParserManager.parse(ParserManager.java:102)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work.indexEmbedding(RepositoryUpdater.java:2673)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work.doIndex(RepositoryUpdater.java:2465)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work.access$1500(RepositoryUpdater.java:1979)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work$2.run(RepositoryUpdater.java:2235)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work$2.run(RepositoryUpdater.java:2233)
   at org.netbeans.modules.parsing.impl.indexing.errors.TaskCache.refreshTransaction(TaskCache.java:462)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work.index(RepositoryUpdater.java:2233)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$AbstractRootsWork.scanSource(RepositoryUpdater.java:4607)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$AbstractRootsWork.scanSources(RepositoryUpdater.java:4360)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$RootsWork.getDone(RepositoryUpdater.java:4081)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work.doTheWork(RepositoryUpdater.java:2851)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Task._run(RepositoryUpdater.java:4998)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Task.access$4800(RepositoryUpdater.java:4710)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Task$2.run(RepositoryUpdater.java:4942)
   at org.netbeans.modules.parsing.impl.RunWhenScanFinishedSupport.performScan(RunWhenScanFinishedSupport.java:90)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Task.run(RepositoryUpdater.java:4938)
   at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
   at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
   at java.util.concurrent.FutureTask.run(FutureTask.java:138)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1411)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1991)