java.lang.AssertionError
   at org.openide.explorer.ExplorerActionsImpl$BaseAction.syncEnable(ExplorerActionsImpl.java:542)
   at org.openide.explorer.ExplorerActionsImpl.syncActions(ExplorerActionsImpl.java:434)
   at org.openide.explorer.ExplorerActionsImpl.updateActionsState(ExplorerActionsImpl.java:430)
   at org.openide.explorer.ExplorerActionsImpl.access$200(ExplorerActionsImpl.java:91)
   at org.openide.explorer.ExplorerActionsImpl$DeleteActionPerformer.isEnabled(ExplorerActionsImpl.java:618)
   at org.openide.util.actions.CallbackSystemAction.updateEnabled(CallbackSystemAction.java:173)
   at org.openide.util.actions.CallbackSystemAction.initialize(CallbackSystemAction.java:115)
   at org.openide.actions.DeleteAction.initialize(DeleteAction.java:61)
   at org.openide.util.SharedClassObject$DataEntry.tryToInitialize(SharedClassObject.java:941)
   at org.openide.util.SharedClassObject$DataEntry.getMap(SharedClassObject.java:867)
   at org.openide.util.SharedClassObject.putProperty(SharedClassObject.java:317)
   at org.openide.util.SharedClassObject.putProperty(SharedClassObject.java:343)
   at org.openide.util.actions.SystemAction.putValue(SystemAction.java:161)
   at org.openide.actions.DeleteAction.<init>(DeleteAction.java:57)
Caused: java.lang.reflect.InvocationTargetException
   at sun.reflect.NativeConstructorAccessorImpl.newInstance0(NativeConstructorAccessorImpl.java:0)
   at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
   at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
   at java.lang.reflect.Constructor.newInstance(Constructor.java:525)
   at org.openide.util.SharedClassObject.createInstancePrivileged(SharedClassObject.java:658)
   at org.openide.util.SharedClassObject$SetAccessibleAction.run(SharedClassObject.java:1018)
   at org.openide.util.SharedClassObject$SetAccessibleAction.run(SharedClassObject.java:1010)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
Caused: java.lang.IllegalArgumentException: java.lang.reflect.InvocationTargetException
   at org.openide.util.SharedClassObject.findObject(SharedClassObject.java:535)
   at org.openide.util.actions.SystemAction.get(SystemAction.java:123)
   at org.netbeans.modules.properties.KeyNode.<init>(KeyNode.java:102)
   at org.netbeans.modules.properties.PropertiesFileEntry$PropKeysChildren.createNodes(PropertiesFileEntry.java:474)
   at org.netbeans.modules.properties.PropertiesFileEntry$PropKeysChildren.createNodes(PropertiesFileEntry.java:406)
   at org.openide.nodes.Children$Keys$KE.nodes(Children.java:1654)
   at org.openide.nodes.ChildrenArray.nodesFor(ChildrenArray.java:149)
   at org.openide.nodes.EntrySupport$Default$Info.nodes(EntrySupport.java:943)
   at org.openide.nodes.EntrySupport$Default.justComputeNodes(EntrySupport.java:253)
   at org.openide.nodes.ChildrenArray.nodes(ChildrenArray.java:88)
   at org.openide.nodes.EntrySupport$Default.getNodes(EntrySupport.java:183)
   at org.openide.nodes.EntrySupport$Default.getNodes(EntrySupport.java:228)
   at org.openide.nodes.Children.getNodes(Children.java:462)
   at org.openide.nodes.FilterNode$Children$DefaultSupport.updateKeys(FilterNode.java:1699)
   at org.openide.nodes.FilterNode$Children$DefaultSupport.update(FilterNode.java:1686)
   at org.openide.nodes.FilterNode$Children.addNotifyImpl(FilterNode.java:1477)
   at org.openide.nodes.FilterNode$Children.addNotify(FilterNode.java:1470)
   at org.openide.nodes.Children.callAddNotify(Children.java:568)
   at org.openide.nodes.EntrySupport$Default.getArray(EntrySupport.java:770)
   at org.openide.nodes.EntrySupport$Default.getNodes(EntrySupport.java:172)
   at org.openide.nodes.EntrySupport$Default.getNodes(EntrySupport.java:228)
   at org.openide.nodes.Children.getNodes(Children.java:462)
   at org.openide.nodes.FilterNode$Children$DefaultSupport.updateKeys(FilterNode.java:1699)
   at org.openide.nodes.FilterNode$Children$DefaultSupport.update(FilterNode.java:1686)
   at org.openide.nodes.FilterNode$Children.addNotifyImpl(FilterNode.java:1477)
   at org.openide.nodes.FilterNode$Children.addNotify(FilterNode.java:1470)
   at org.openide.nodes.Children.callAddNotify(Children.java:568)
   at org.openide.nodes.EntrySupport$Default.getArray(EntrySupport.java:770)
   at org.openide.nodes.EntrySupport$Default.getNodes(EntrySupport.java:172)
   at org.openide.nodes.EntrySupport$Default.getNodes(EntrySupport.java:228)
   at org.openide.nodes.EntrySupport$Default.getNodesCount(EntrySupport.java:232)
   at org.openide.nodes.Children.getNodesCount(Children.java:502)
   at org.openide.nodes.Node$1.run(Node.java:526)
   at org.openide.util.Mutex.postRequest(Mutex.java:1267)
   at org.openide.util.Mutex.postRequest(Mutex.java:1213)
   at org.openide.util.Mutex.postWriteRequest(Mutex.java:585)
   at org.openide.nodes.Node.setChildren(Node.java:500)
   at org.openide.nodes.FilterNode.changeOriginal(FilterNode.java:448)
   at org.openide.loaders.FolderChildren$DelayedNode.run(FolderChildren.java:427)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1424)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1973)