org.netbeans.modules.xml.spi.dom.UOException: This read-only implementation supports DOM level 1 Core and XML module.
	at org.netbeans.modules.xml.text.syntax.SyntaxElement.getNext(SyntaxElement.java:109)
	at org.netbeans.modules.xml.text.syntax.dom.SyntaxNode.findNext(SyntaxNode.java:99)
	at org.netbeans.modules.xml.text.syntax.dom.SyntaxNode.findNext(SyntaxNode.java:111)
	at org.netbeans.modules.xml.text.syntax.dom.StartTag.getEndTag(StartTag.java:57)
	at org.netbeans.modules.xml.text.syntax.dom.StartTag.getEndTag(StartTag.java:70)
	at org.netbeans.modules.xml.text.syntax.dom.StartTag.getEndTag(StartTag.java:70)
	at org.netbeans.modules.xml.text.syntax.dom.StartTag.getEndTag(StartTag.java:70)
	at org.netbeans.modules.xml.text.syntax.dom.StartTag.getEndTag(StartTag.java:70)
	at org.netbeans.modules.xml.text.syntax.dom.StartTag.getEndTag(StartTag.java:70)
	at org.netbeans.modules.xml.text.syntax.dom.Tag.getNextSibling(Tag.java:231)
	at org.netbeans.modules.xml.text.syntax.dom.StartTag.getChildNodes(StartTag.java:45)
	at org.netbeans.modules.xml.text.syntax.dom.Tag.getFirstChild(Tag.java:242)
	at org.netbeans.modules.xsl.grammar.XSLGrammarQuery.updateProperties(XSLGrammarQuery.java:900)
	at org.netbeans.modules.xsl.grammar.XSLGrammarQuery.queryValues(XSLGrammarQuery.java:558)
	at org.netbeans.modules.xml.text.completion.XMLCompletionQuery.queryValues(XMLCompletionQuery.java:289)
	at org.netbeans.modules.xml.text.completion.XMLCompletionQuery.query(XMLCompletionQuery.java:119)
	at org.netbeans.editor.ext.Completion.performQuery(Completion.java:594)
	at org.netbeans.editor.ext.Completion.access$700(Completion.java:47)
	at org.netbeans.editor.ext.Completion$1QueryTask.run(Completion.java:524)
	at org.openide.util.Task.run(Task.java:136)
	at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:330)
[catch] at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:678)