java.lang.NullPointerException: The fileObject parameter cannot be null
   at org.openide.util.Parameters.notNull(Parameters.java:89)
   at org.netbeans.modules.parsing.api.Source.create(Source.java:127)
   at org.netbeans.modules.web.el.refactoring.ELRefactoringPlugin.getParserResult(ELRefactoringPlugin.java:123)
   at org.netbeans.modules.web.el.refactoring.ELWhereUsedQuery.getMatchingElements(ELWhereUsedQuery.java:363)
   at org.netbeans.modules.web.el.refactoring.ELWhereUsedQuery.handleProperty(ELWhereUsedQuery.java:174)
   at org.netbeans.modules.web.el.refactoring.ELWhereUsedQuery.prepare(ELWhereUsedQuery.java:121)
   at org.netbeans.modules.refactoring.api.AbstractRefactoring.pluginsPrepare2(AbstractRefactoring.java:419)
   at org.netbeans.modules.refactoring.api.AbstractRefactoring.pluginsPrepare(AbstractRefactoring.java:403)
   at org.netbeans.modules.refactoring.api.AbstractRefactoring.prepare(AbstractRefactoring.java:218)
   at org.netbeans.modules.refactoring.spi.impl.ParametersPanel$Prepare.run(ParametersPanel.java:851)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1424)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1968)