java.lang.NullPointerException
   at org.netbeans.modules.form.FormDataObject.createNodeDelegate(FormDataObject.java:171)
   at org.openide.loaders.DataObject$1.run(DataObject.java:332)
   at org.openide.util.Mutex.readAccess(Mutex.java:372)
   at org.openide.util.Mutex$1R.run(Mutex.java:1322)
   at org.openide.nodes.Children$ProjectManagerDeadlockDetector.execute(Children.java:1921)
   at org.openide.util.Mutex.doWrapperAccess(Mutex.java:1341)
   at org.openide.util.Mutex.readAccess(Mutex.java:361)
   at org.openide.loaders.DataObject.getNodeDelegateImpl(DataObject.java:328)
   at org.openide.loaders.DataObject.getNodeDelegate(DataObject.java:320)
   at org.netbeans.modules.form.FormDataObject.getLookup(FormDataObject.java:113)
   at org.netbeans.modules.parsing.api.Source.getDocument(Source.java:261)
   at org.netbeans.modules.parsing.api.Source.createSnapshot(Source.java:313)
   at org.netbeans.modules.parsing.impl.SourceCache.createSnapshot(SourceCache.java:179)
   at org.netbeans.modules.parsing.impl.SourceCache.getSnapshot(SourceCache.java:154)
   at org.netbeans.modules.parsing.impl.SourceCache.getParser(SourceCache.java:199)
   at org.netbeans.modules.parsing.impl.SourceCache.createTasks(SourceCache.java:483)
   at org.netbeans.modules.parsing.impl.SourceCache.scheduleTasks(SourceCache.java:521)
   at org.netbeans.modules.parsing.spi.Scheduler$2.run(Scheduler.java:219)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1423)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2033)