Steps to reproduce:
0. Open or create new Synchronous BPEL Process sample. Deploy it.
1. Run TestCase 5 or more times.
2. Select all test results and delete it.

The exception is generated:

"java.lang.IllegalStateException: The data object
MasterFileObject@189f393[C:/WORK/PredefinedSamples/SynchronousSample/SynchronousSampleApplication/test/results/TestCase0/Actual_20070410145420_S.xml]
is invalid; you may not call getNodeDelegate on it any more; see #17020 and
please fix your code
	at org.openide.loaders.DataObject.getNodeDelegate(DataObject.java:244)
	at org.openide.loaders.DataObject.getLookup(DataObject.java:956)
	at
org.netbeans.modules.bpel.search.impl.action.SearchAction.getBpelModel(SearchAction.java:61)
	at
org.netbeans.modules.bpel.search.impl.action.SearchAction.enable(SearchAction.java:53)
	at org.openide.util.actions.NodeAction.isEnabled(NodeAction.java:180)
	at org.openide.awt.Actions$ButtonBridge.updateState(Actions.java:738)
	at org.openide.awt.Actions$Bridge.propertyChange(Actions.java:531)
	at
java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:333)
	at
java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:270)
	at
org.openide.util.SharedClassObject.firePropertyChange(SharedClassObject.java:432)
	at org.openide.util.actions.NodeAction.maybeFireEnabledChange(NodeAction.java:346)
	at org.openide.util.actions.NodeAction$NodesL$1.run(NodeAction.java:500)
	at org.openide.util.Mutex.doEvent(Mutex.java:1181)
	at org.openide.util.Mutex.readAccess(Mutex.java:287)
	at org.openide.util.actions.NodeAction$NodesL.forget(NodeAction.java:498)
	at org.openide.util.actions.NodeAction$NodesL.update(NodeAction.java:467)
	at org.openide.util.actions.NodeAction$NodesL.resultChanged(NodeAction.java:460)
	at org.openide.util.lookup.ProxyLookup.setLookups(ProxyLookup.java:170)
	at org.openide.explorer.DefaultEMLookup.updateLookups(DefaultEMLookup.java:109)
	at org.openide.explorer.DefaultEMLookup.propertyChange(DefaultEMLookup.java:141)
	at
org.openide.util.WeakListenerImpl$PropertyChange.propertyChange(WeakListenerImpl.java:164)
	at
java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:333)
	at
java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:270)
	at org.openide.explorer.ExplorerManager$2.run(ExplorerManager.java:809)
	at org.openide.util.Mutex.doEvent(Mutex.java:1181)
	at org.openide.util.Mutex.readAccess(Mutex.java:287)
	at org.openide.explorer.ExplorerManager.fireInAWT(ExplorerManager.java:806)
	at org.openide.explorer.ExplorerManager.access$600(ExplorerManager.java:65)
	at
org.openide.explorer.ExplorerManager$1AtomicSetSelectedNodes.fire(ExplorerManager.java:262)
	at org.openide.explorer.ExplorerManager.setSelectedNodes(ExplorerManager.java:275)
	at
org.openide.explorer.ExplorerManager$1SetExploredContextAndSelection.run(ExplorerManager.java:361)
	at org.openide.util.Mutex.readAccess(Mutex.java:296)
	at
org.openide.explorer.ExplorerManager.setExploredContextAndSelection(ExplorerManager.java:386)
	at org.openide.explorer.view.BeanTreeView.selectionChanged(BeanTreeView.java:133)
	at org.openide.explorer.view.TreeView.callSelectionChanged(TreeView.java:721)
	at org.openide.explorer.view.TreeView$TreePropertyListener.run(TreeView.java:1277)
	at org.openide.util.Mutex.postRequest(Mutex.java:1151)
	at org.openide.util.Mutex.postReadRequest(Mutex.java:473)
	at
org.openide.explorer.view.TreeView$TreePropertyListener.valueChanged(TreeView.java:1248)
	at
javax.swing.tree.DefaultTreeSelectionModel.fireValueChanged(DefaultTreeSelectionModel.java:629)
	at
javax.swing.tree.DefaultTreeSelectionModel.notifyPathChange(DefaultTreeSelectionModel.java:1078)
	at
javax.swing.tree.DefaultTreeSelectionModel.setSelectionPaths(DefaultTreeSelectionModel.java:287)
	at
javax.swing.tree.DefaultTreeSelectionModel.setSelectionPath(DefaultTreeSelectionModel.java:170)
	at javax.swing.JTree.setSelectionPath(JTree.java:1174)
	at
org.openide.explorer.view.TreeView$ExplorerTree$ModelHandler.treeNodesRemoved(TreeView.java:2059)
	at
javax.swing.tree.DefaultTreeModel.fireTreeNodesRemoved(DefaultTreeModel.java:528)
	at javax.swing.tree.DefaultTreeModel.nodesWereRemoved(DefaultTreeModel.java:308)
	at org.openide.explorer.view.NodeTreeModel$Listener.removed(NodeTreeModel.java:175)
	at
org.openide.explorer.view.VisualizerChildren.removed(VisualizerChildren.java:143)
	at org.openide.explorer.view.VisualizerEvent$Removed.run(VisualizerEvent.java:123)
	at org.openide.util.Mutex.readAccess(Mutex.java:296)
[catch] at org.openide.explorer.view.VisualizerNode$QP.run(VisualizerNode.java:660)
	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)"