java.lang.NullPointerException
        at org.netbeans.modules.refactoring.java.ui.SafeDeletePanel$1.run(SafeDeletePanel.java:112)
        at org.netbeans.modules.refactoring.java.ui.SafeDeletePanel$1.run(SafeDeletePanel.java:110)
        at org.netbeans.api.java.source.JavaSource.runUserActionTask(JavaSource.java:579)
        at org.netbeans.modules.refactoring.java.ui.SafeDeletePanel.initialize(SafeDeletePanel.java:106)
        at org.netbeans.modules.refactoring.spi.impl.ParametersPanel$10.run(ParametersPanel.java:458)
        at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:539)
        at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:964)