Not always reproduced.

1. add testpack
2. use 'Refresh' on test tree root
3. following exception occures:

Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: 7 > 6
        at java.util.Vector.insertElementAt(Vector.java:558)
        at javax.swing.tree.DefaultMutableTreeNode.insert(DefaultMutableTreeNode.java:177)
        at javax.swing.tree.VariableHeightLayoutCache.createNodeAt(VariableHeightLayoutCache.java:763)
        at javax.swing.tree.VariableHeightLayoutCache.treeNodesInserted(VariableHeightLayoutCache.java:473)
        at javax.swing.plaf.basic.BasicTreeUI$Handler.treeNodesInserted(BasicTreeUI.java:3621)
        at com.sun.javatest.exec.TestTreeModel$Notifier.run(TestTreeModel.java:1065)
        at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:461)
        at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:242)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:163)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:157)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:149)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:110)