java.lang.IllegalStateException: The manager has been already released
   at org.netbeans.modules.editor.fold.FoldHierarchyTransactionImpl.addFold(FoldHierarchyTransactionImpl.java:540)
   at org.netbeans.modules.editor.fold.FoldHierarchyExecution.add(FoldHierarchyExecution.java:390)
   at org.netbeans.modules.editor.fold.FoldOperationImpl.addToHierarchy(FoldOperationImpl.java:185)
   at org.netbeans.spi.editor.fold.FoldOperation.addToHierarchy(FoldOperation.java:140)
   at org.netbeans.modules.editor.fold.support.FoldMaintainerImpl.install(FoldMaintainerImpl.java:249)
   at org.netbeans.modules.editor.fold.support.FoldMaintainerImpl$2.run(FoldMaintainerImpl.java:209)
   at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:251)
   at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:721)
   at java.awt.EventQueue.access$200(EventQueue.java:103)
   at java.awt.EventQueue$3.run(EventQueue.java:682)
   at java.awt.EventQueue$3.run(EventQueue.java:680)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
   at java.awt.EventQueue.dispatchEvent(EventQueue.java:691)
   at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:159)
   at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:244)
   at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:163)
   at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:147)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:139)
   at java.awt.EventDispatchThread.run(EventDispatchThread.java:97)