java.lang.IllegalStateException: The manager has been already released
   at org.netbeans.modules.editor.fold.FoldHierarchyTransactionImpl.addFold(FoldHierarchyTransactionImpl.java:695)
   at org.netbeans.modules.editor.fold.FoldHierarchyExecution.add(FoldHierarchyExecution.java:488)
   at org.netbeans.modules.editor.fold.FoldOperationImpl.addToHierarchy(FoldOperationImpl.java:207)
   at org.netbeans.spi.editor.fold.FoldOperation.addToHierarchy(FoldOperation.java:147)
   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:311)
   at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:744)
   at java.awt.EventQueue.access$400(EventQueue.java:97)
   at java.awt.EventQueue$3.run(EventQueue.java:697)
   at java.awt.EventQueue$3.run(EventQueue.java:691)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
   at java.awt.EventQueue.dispatchEvent(EventQueue.java:714)
   at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:159)
   at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
   at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
   at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
   at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)