java.lang.IllegalArgumentException: A node selection cannot contain nodes (br) not underneath the root (null).
        at org.openide.explorer.ExplorerManager.checkUnderRoot(ExplorerManager.java:561)
        at org.openide.explorer.ExplorerManager.access$300(ExplorerManager.java:87)
        at org.openide.explorer.ExplorerManager$1AtomicSetSelectedNodes.checkArgumentIsValid(ExplorerManager.java:232)
        at org.openide.explorer.ExplorerManager$1AtomicSetSelectedNodes.run(ExplorerManager.java:265)
        at org.openide.util.Mutex.readAccess(Mutex.java:362)
        at org.openide.explorer.ExplorerManager.setSelectedNodes(ExplorerManager.java:272)
        at org.netbeans.modules.gsfret.navigation.ClassMemberPanelUI.selectElementNode(ClassMemberPanelUI.java:171)
        at org.netbeans.modules.gsfret.navigation.ClassMemberPanel.selectElement(ClassMemberPanel.java:97)
        at org.netbeans.modules.gsfret.navigation.CaretListeningTask.run(CaretListeningTask.java:77)
        at org.netbeans.modules.gsfret.navigation.CaretListeningTask.run(CaretListeningTask.java:57)
        at org.netbeans.napi.gsfret.source.Source$CompilationJob.run(Source.java:1216)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
        at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
        at java.util.concurrent.FutureTask.run(FutureTask.java:138)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:885)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:907)
        at java.lang.Thread.run(Thread.java:637)