java.lang.AssertionError: Token length=-38 <= 0
        at org.netbeans.lib.lexer.token.DefaultToken.<init>(DefaultToken.java:84)
        at org.netbeans.lib.lexer.token.PropertyToken.<init>(PropertyToken.java:61)
        at org.netbeans.lib.lexer.token.PartToken.<init>(PartToken.java:67)
        at org.netbeans.lib.lexer.JoinLexerInputOperation.createJoinToken(JoinLexerInputOperation.java:263)
        at org.netbeans.lib.lexer.JoinLexerInputOperation.createDefaultTokenInstance(JoinLexerInputOperation.java:237)
        at org.netbeans.lib.lexer.LexerInputOperation.createToken(LexerInputOperation.java:269)
        at org.netbeans.spi.lexer.TokenFactory.createToken(TokenFactory.java:102)
        at org.netbeans.spi.lexer.TokenFactory.createToken(TokenFactory.java:86)
        at org.netbeans.modules.css.lexer.CSSLexer.nextToken(CSSLexer.java:111)
        at org.netbeans.lib.lexer.LexerInputOperation.nextToken(LexerInputOperation.java:184)
        at org.netbeans.lib.lexer.inc.TokenListUpdater.relex(TokenListUpdater.java:580)
        at org.netbeans.lib.lexer.inc.TokenListUpdater.updateJoined(TokenListUpdater.java:542)
        at org.netbeans.lib.lexer.inc.TokenHierarchyUpdate$UpdateItem.update(TokenHierarchyUpdate.java:333)
        at org.netbeans.lib.lexer.inc.TokenHierarchyUpdate.processLevelInfos(TokenHierarchyUpdate.java:215)
        at org.netbeans.lib.lexer.inc.TokenHierarchyUpdate.updateCreateOrRemoveEmbedding(TokenHierarchyUpdate.java:204)
        at org.netbeans.lib.lexer.EmbeddingContainer.createEmbedding(EmbeddingContainer.java:282)
        at org.netbeans.api.lexer.TokenSequence.createEmbedding(TokenSequence.java:418)
        at org.netbeans.modules.html.editor.coloring.EmbeddingUpdater.createEmbedding(EmbeddingUpdater.java:303)
        at org.netbeans.modules.html.editor.coloring.EmbeddingUpdater.createEmbedding(EmbeddingUpdater.java:241)
        at org.netbeans.modules.html.editor.coloring.EmbeddingUpdater.startTag(EmbeddingUpdater.java:149)
        at org.netbeans.modules.html.editor.coloring.EmbeddingUpdater.parsingFinished(EmbeddingUpdater.java:120)
        at org.netbeans.editor.ext.html.parser.SyntaxParser.notifyParsingFinished(SyntaxParser.java:238)
        at org.netbeans.editor.ext.html.parser.SyntaxParser.parse(SyntaxParser.java:222)
        at org.netbeans.editor.ext.html.parser.SyntaxParser.access$200(SyntaxParser.java:69)
        at org.netbeans.editor.ext.html.parser.SyntaxParser$4.run(SyntaxParser.java:151)
        at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:572)
        at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:997)