antlr file in netbeans has error

Peter Cheung <[email protected]> Sat, 19 Aug 2017 19:18:18 +0000
Newsgroups gmane.comp.java.netbeans.modules.openide.devel
Message-ID <ME1PR01MB02602EE2095C81FEC36FFAADB5810@ME1PR01MB0260.ausprd01.prod.outlook.com>
hi, i didn't install any antlr plugin but my antlr files are displayed as error. why?

Thanks
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