java.lang.IllegalStateException: The data object MultiFileObject@59f401[Templates/Project/Samples/Standard] is invalid; you may not call getNodeDelegate on it any more; see #17020 and please fix your code
        at org.openide.loaders.DataObject.getNodeDelegate(DataObject.java:270)
        at org.netbeans.modules.project.ui.TemplatesPanel$CategoriesChildren.createNodes(TemplatesPanel.java:220)
        at org.netbeans.modules.project.ui.TemplatesPanel$CategoriesChildren.createNodes(TemplatesPanel.java:192)
        at org.openide.nodes.Children$Keys$KE.nodes(Children.java:1517)
        at org.openide.nodes.ChildrenArray.nodesFor(ChildrenArray.java:168)
        at org.openide.nodes.EntrySupport$Default$Info.nodes(EntrySupport.java:935)
        at org.openide.nodes.EntrySupport$Default.updateAdd(EntrySupport.java:502)
        at org.openide.nodes.EntrySupport$Default.setEntries(EntrySupport.java:335)
        at org.openide.nodes.Children$Keys$2.run(Children.java:1411)
        at org.openide.util.Mutex.leaveImpl(Mutex.java:902)
        at org.openide.util.Mutex.leave(Mutex.java:835)
        at org.openide.util.Mutex.readAccess(Mutex.java:364)
        at org.openide.explorer.view.VisualizerNode$QP.run(VisualizerNode.java:670)
        at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:597)
        at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:104)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:273)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:183)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:173)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:168)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:160)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:121)