java.lang.IllegalArgumentException: view is invalid
   at javax.help.search.MergingSearchEngine.merge(MergingSearchEngine.java:91)
   at org.netbeans.modules.javahelp.JavaHelp.createSearchEngine(JavaHelp.java:200)
   at org.netbeans.modules.javahelp.JavaHelpQuery.createSearchEngine(JavaHelpQuery.java:154)
   at org.netbeans.modules.javahelp.JavaHelpQuery.search(JavaHelpQuery.java:104)
   at org.netbeans.modules.javahelp.JavaHelpQuickSearchProviderImpl.evaluate(JavaHelpQuickSearchProviderImpl.java:70)
   at org.netbeans.modules.quicksearch.CommandEvaluator$1.run(CommandEvaluator.java:201)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1424)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1968)
Caused: org.openide.util.RequestProcessor$SlowItem: task failed due to: java.lang.IllegalArgumentException: view is invalid
   at org.openide.util.RequestProcessor.post(RequestProcessor.java:425)
   at org.netbeans.modules.quicksearch.CommandEvaluator.runEvaluation(CommandEvaluator.java:198)
   at org.netbeans.modules.quicksearch.CommandEvaluator.evaluate(CommandEvaluator.java:103)
   at org.netbeans.modules.quicksearch.QuickSearchPopup.actionPerformed(QuickSearchPopup.java:175)
   at javax.swing.Timer.fireActionPerformed(Timer.java:271)
   at javax.swing.Timer$DoPostEvent.run(Timer.java:201)
   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:148)
   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)