java.lang.NullPointerException
        at org.netbeans.modules.refactoring.java.ui.SafeDeletePanel$1.run(SafeDeletePanel.java:134)
        at org.netbeans.modules.refactoring.java.ui.SafeDeletePanel$1.run(SafeDeletePanel.java:132)
        at org.netbeans.api.java.source.JavaSource.runUserActionTask(JavaSource.java:616)
        at org.netbeans.modules.refactoring.java.ui.SafeDeletePanel.initialize(SafeDeletePanel.java:128)
        at org.netbeans.modules.refactoring.spi.impl.ParametersPanel$10.run(ParametersPanel.java:485)
        at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:561)
        at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:986)