Had a JWindow subclass I had just created, open with errors (will attach).  I right clicked over the word 
"class" in the definition for the inner class L, and the popup menu appeared, but the following 
exception was also thrown:

java.lang.InterruptedException
	at java.lang.Object.wait(Native Method)
	at java.lang.Object.wait(Object.java:429)
	at org.openide.util.Mutex$QueueCell.sleep(Mutex.java:1388)
	at org.openide.util.Mutex.enter(Mutex.java:608)
	at org.openide.util.Mutex.readEnter(Mutex.java:488)
	at org.openide.util.Mutex.access$000(Mutex.java:78)
	at org.openide.util.Mutex$Privileged.enterReadAccess(Mutex.java:1434)
	at org.netbeans.modules.masterfs.filebasedfs.fileobjects.FolderObj.getFileObject(FolderObj.java:
64)
	at org.netbeans.modules.masterfs.MasterFileObject.getFileObject(MasterFileObject.java:272)
	at org.openide.filesystems.FileObject.getFileObject(FileObject.java:589)
	at org.netbeans.modules.javacore.JMManager.getFileObject(JMManager.java:604)
	at 
org.netbeans.modules.javacore.jmiimpl.javamodel.ResourceImpl.checkUpToDate(ResourceImpl.java:
567)
	at 
org.netbeans.modules.javacore.jmiimpl.javamodel.SemiPersistentElement.isValid(SemiPersistentElement
.java:67)
	at org.netbeans.modules.java.JavaEditor$JavaEditorComponent.createNode(JavaEditor.java:1249)
	at org.netbeans.modules.java.JavaEditor$JavaEditorComponent.access$800(JavaEditor.java:1168)
	at org.netbeans.modules.java.JavaEditor$12.run(JavaEditor.java:1220)
	at org.openide.util.Mutex.readAccess(Mutex.java:195)
	at org.netbeans.modules.java.JavaEditor$11.run(JavaEditor.java:1218)
	at org.openide.util.Task.run(Task.java:207)
	at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:435)
[catch] at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:836)