1. open parenBP.bpel in the attached project
2. Go to line 166
3. delte isolated="no"
4. Save the file using "save" button on tool bar it runs into this error.
where as Ctrl + S there is no issue.

java.lang.IllegalStateException: Assertion failed. WindowsAPI is required to be
called from AWT thread only, see http://core.netbeans.org/proposals/threading/
	at
org.netbeans.core.windows.WindowManagerImpl.assertEventDispatchThreadWeak(WindowManagerImpl.java:1432)
	at
org.netbeans.core.windows.WindowManagerImpl.findTopComponent(WindowManagerImpl.java:213)
	at
org.netbeans.modules.bpel.xpath.view.output.ResultWindow.getInstance(ResultWindow.java:75)
	at
org.netbeans.modules.bpel.xpath.view.output.DesignContextSynchronizationListener.hasView(DesignContextSynchronizationListener.java:121)
	at
org.netbeans.modules.bpel.xpath.view.output.DesignContextSynchronizationListener.handleChangeEvent(DesignContextSynchronizationListener.java:102)
	at
org.netbeans.modules.bpel.xpath.view.output.DesignContextSynchronizationListener.notifyPropertyUpdated(DesignContextSynchronizationListener.java:75)
	at
org.netbeans.modules.bpel.model.api.events.ChangeEventSupport.notifyChangeEvent(ChangeEventSupport.java:176)
	at
org.netbeans.modules.bpel.model.api.events.ChangeEventSupport.fireChangeEvent(ChangeEventSupport.java:152)
	at
org.netbeans.modules.bpel.model.impl.BpelModelImpl$Transaction.commitEvents(BpelModelImpl.java:920)
	at
org.netbeans.modules.bpel.model.impl.BpelModelImpl$Transaction.end(BpelModelImpl.java:832)
	at
org.netbeans.modules.bpel.model.impl.BpelModelImpl.writeUnlock(BpelModelImpl.java:663)
	at org.netbeans.modules.bpel.model.impl.BpelModelImpl.sync(BpelModelImpl.java:392)
	at
org.netbeans.modules.bpel.core.BPELDataEditorSupport.syncModel(BPELDataEditorSupport.java:154)
	at
org.netbeans.modules.bpel.core.BPELDataEditorSupport.saveDocument(BPELDataEditorSupport.java:143)
	at org.netbeans.modules.bpel.core.BPELDataObject$1.save(BPELDataObject.java:123)
	at org.netbeans.core.NbTopManager.saveAll(NbTopManager.java:261)
	at org.netbeans.core.NbTopManager.access$300(NbTopManager.java:68)
	at org.netbeans.core.NbTopManager$NbLifecycleManager.saveAll(NbTopManager.java:418)
	at org.openide.actions.SaveAllAction.performAction(SaveAllAction.java:81)
	at
org.openide.util.actions.CallableSystemAction$1.run(CallableSystemAction.java:96)
	at
org.netbeans.modules.openide.util.ActionsBridge$ActionRunnable.actionPerformed(ActionsBridge.java:89)
	at org.netbeans.core.ModuleActions.invokeAction(ModuleActions.java:82)
	at
org.netbeans.modules.openide.actions.ActionsBridgeImpl.invokeAction(ActionsBridgeImpl.java:30)
	at
org.netbeans.modules.openide.util.ActionsBridge$ActionRunnable.doRun(ActionsBridge.java:80)
	at org.netbeans.modules.openide.util.ActionsBridge$1.run(ActionsBridge.java:49)
	at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:539)
[catch] at
org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:964)