java.lang.AssertionError: BaseKit.install() incorrectly called from non-AWT thread.
        at org.netbeans.editor.BaseKit.install(BaseKit.java:517)
        at org.netbeans.modules.lexer.editorbridge.LexerEditorKit.install(LexerEditorKit.java:76)
        at org.netbeans.modules.languages.LanguagesEditorKit.install(LanguagesEditorKit.java:218)
        at javax.swing.JEditorPane.setEditorKit(JEditorPane.java:959)
        at org.openide.text.CloneableEditor.initialize(CloneableEditor.java:194)
        at org.openide.text.CloneableEditor.getEditorPane(CloneableEditor.java:608)
        at org.openide.text.CloneableEditorSupport.getOpenedPanes(CloneableEditorSupport.java:850)
        at org.netbeans.modules.languages.fold.LanguagesNavigator.refresh(LanguagesNavigator.java:166)
        at org.netbeans.modules.languages.fold.LanguagesNavigator.access$200(LanguagesNavigator.java:66)
        at org.netbeans.modules.languages.fold.LanguagesNavigator$DocumentListener.parsed(LanguagesNavigator.java:574)
        at org.netbeans.modules.languages.ParserManager.setChange(ParserManager.java:121)
        at org.netbeans.modules.languages.ParserManager.parseAST(ParserManager.java:149)
        at org.netbeans.modules.languages.ParserManager.access$100(ParserManager.java:39)
        at org.netbeans.modules.languages.ParserManager$1.run(ParserManager.java:109)
        at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:541)
[catch] at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:963)