java.lang.IllegalStateException: Should not acquire Children.MUTEX while holding ProjectManager.mutex()
        at org.openide.nodes.Children$ProjectManagerDeadlockDetector.execute(Children.java:1805)
        at org.openide.util.Mutex.doWrapperAccess(Mutex.java:1320)
        at org.openide.util.Mutex.readAccess(Mutex.java:351)
        at org.openide.explorer.ExplorerManager.setRootContext(ExplorerManager.java:499)
        at org.openide.explorer.ExplorerManager$Listener.nodeDestroyed(ExplorerManager.java:910)
Caused: java.lang.reflect.InvocationTargetException
        at sun.reflect.GeneratedMethodAccessor103.invoke(GeneratedMethodAccessor103.java:0)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at org.openide.util.WeakListenerImpl$ProxyListener.invoke(WeakListenerImpl.java:450)
Caused: java.lang.reflect.UndeclaredThrowableException
        at $Proxy5.nodeDestroyed(.java:0)
        at org.openide.nodes.Node.fireNodeDestroyed(Node.java:1172)
        at org.openide.loaders.DataNode.access$800(DataNode.java:64)
        at org.openide.loaders.DataNode$4.run(DataNode.java:772)
        at org.openide.util.Mutex.doEvent(Mutex.java:1335)
        at org.openide.util.Mutex.writeAccess(Mutex.java:452)
        at org.openide.loaders.DataNode.fireChange(DataNode.java:739)
        at org.openide.loaders.DataNode$PropL.propertyChange(DataNode.java:882)
        at org.openide.util.WeakListenerImpl$PropertyChange.propertyChange(WeakListenerImpl.java:187)
        at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:339)
        at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:276)
        at org.openide.loaders.DataObject.firePropertyChange(DataObject.java:910)
        at org.openide.loaders.DataObject.dispose(DataObject.java:191)
        at org.openide.loaders.DataObject.markInvalid0(DataObject.java:214)
        at org.openide.loaders.MultiDataObject.notifyFileDeleted(MultiDataObject.java:1234)
        at org.openide.loaders.DataObjectPool$FSListener.fileDeleted(DataObjectPool.java:633)
        at org.openide.filesystems.FCLSupport$DispatchEventWrapper.dispatchEventImpl(FCLSupport.java:139)
        at org.openide.filesystems.FCLSupport$DispatchEventWrapper.dispatchEvent(FCLSupport.java:122)
        at org.openide.filesystems.FCLSupport.dispatchEvent(FCLSupport.java:99)
        at org.openide.filesystems.FileObject$ED.dispatch(FileObject.java:1052)
        at org.openide.filesystems.FileSystem$EventDispatcher.run(FileSystem.java:925)
        at org.openide.filesystems.EventControl.dispatchEvent(EventControl.java:77)
        at org.openide.filesystems.FileSystem.dispatchEvent(FileSystem.java:544)
        at org.openide.filesystems.FileObject.dispatchEvent(FileObject.java:469)
        at org.openide.filesystems.FileObject.fireFileDeletedEvent(FileObject.java:445)
        at org.netbeans.modules.masterfs.filebasedfs.fileobjects.BaseFileObj.fireFileDeletedEvent(BaseFileObj.java:539)
        at org.netbeans.modules.masterfs.filebasedfs.fileobjects.BaseFileObj.delete(BaseFileObj.java:629)
        at org.netbeans.modules.masterfs.filebasedfs.fileobjects.BaseFileObj$2.call(BaseFileObj.java:586)
        at org.netbeans.modules.masterfs.filebasedfs.fileobjects.BaseFileObj$2.call(BaseFileObj.java:581)
        at org.netbeans.modules.masterfs.filebasedfs.FileBasedFileSystem.runAsInconsistent(FileBasedFileSystem.java:112)
        at org.netbeans.modules.masterfs.filebasedfs.fileobjects.BaseFileObj.delete(BaseFileObj.java:594)
        at org.openide.filesystems.FileObject.delete(FileObject.java:359)
        at org.netbeans.modules.java.j2seproject.ui.customizer.J2SEProjectProperties.checkModified(J2SEProjectProperties.java:449)
        at org.netbeans.modules.java.j2seproject.ui.customizer.CustomizerProviderImpl$OptionListener.actionPerformed(CustomizerProviderImpl.java:188)
        at org.netbeans.modules.project.uiapi.CustomizerDialog$OptionListener$1.run(CustomizerDialog.java:246)
        at org.openide.util.Mutex.writeAccess(Mutex.java:394)
        at org.netbeans.modules.project.uiapi.CustomizerDialog$OptionListener.actionPerformed(CustomizerDialog.java:244)
        at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
        at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
        at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
        at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
        at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236)
        at java.awt.Component.processMouseEvent(Component.java:6216)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3265)
        at java.awt.Component.processEvent(Component.java:5981)
        at java.awt.Container.processEvent(Container.java:2041)
        at java.awt.Component.dispatchEventImpl(Component.java:4583)
        at java.awt.Container.dispatchEventImpl(Container.java:2099)
        at java.awt.Component.dispatchEvent(Component.java:4413)
        at java.awt.LightweightDispatcher.retargetMouseEvent(LightweightDispatcher.java:4556)
        at java.awt.LightweightDispatcher.processMouseEvent(LightweightDispatcher.java:4220)
        at java.awt.LightweightDispatcher.dispatchEvent(LightweightDispatcher.java:4150)
        at java.awt.Container.dispatchEventImpl(Container.java:2085)
        at java.awt.Window.dispatchEventImpl(Window.java:2475)
        at java.awt.Component.dispatchEvent(Component.java:4413)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
        at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:104)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)