Using the latest 070209_3... two issues:

Open the OTA schema
  File > New Project > Samples > SOA > Travel Reservation Service
  Next; Finish
  in Projects, expand TravelReservationService > Process Files
  Right-click OTA_TravelItinerary.xsd > Open

Issue # 1 - sync b/ SV & DV...probably same as issue 95026
In the source editor, switch to Design view
Right-click CancellationStatus > Add > Attribute (newAttribute)
-> Source view looks fine
Back in DV, click
  Undo -> newAttribute gone from DV & SV; Redo enabled.
  Redo -> in DV, CancellationStatus is changed from boolean to Anonymous type
and Undo enabled; in SV, newAttribute is back.
  Undo -> in DV, CancellationStatus is changed back to boolean; in SV,
newAttribute gone

Issue # 2 - NullPointerException in ABE
In the source editor, close the OTA_TravelItinerary.xsd tab
In Projects, right-click OTA_TravelItinerary.xsd > Open
In the source editor, switch to Design view
Right-click CancellationStatus > Add > Attribute (newAttribute)
-> Source view looks fine
Back in DV, click
  Undo -> in DV, nothing happens and newAttribute remains; Redo enabled;
          in SV, newAttribute gone
  Redo -> exception below.  Note that this occurs only on second round and so
forth, i.e. to reproduce this exception, follow the entire scenario starting
from the steps in issue # 1.

java.lang.NullPointerException
        at
org.netbeans.modules.xml.schema.core.multiview.SchemaABEViewMultiViewElement.emptyUI(SchemaABEViewMultiViewElement.java:256)
        at
org.netbeans.modules.xml.schema.core.multiview.SchemaABEViewMultiViewElement.onModelStateChanged(SchemaABEViewMultiViewElement.java:119)
        at
org.netbeans.modules.xml.schema.core.multiview.SchemaABEViewMultiViewElement.propertyChange(SchemaABEViewMultiViewElement.java:100)
        at sun.reflect.GeneratedMethodAccessor41.invoke(Unknown Source)
        at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at
org.openide.util.WeakListenerImpl$ProxyListener.invoke(WeakListenerImpl.java:416)
        at $Proxy14.propertyChange(Unknown Source)
        at
java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:339)
        at
org.netbeans.modules.xml.xam.AbstractModel.setState(AbstractModel.java:166)
        at org.netbeans.modules.xml.xam.AbstractModel.sync(AbstractModel.java:247)
        at
org.netbeans.modules.xml.axi.impl.AXIModelImpl.sync(AXIModelImpl.java:183)
        at
org.netbeans.modules.xml.xam.ui.undo.QuietUndoManager.syncModel(QuietUndoManager.java:150)
        at
org.netbeans.modules.xml.xam.ui.undo.QuietUndoManager.redo(QuietUndoManager.java:160)
        at org.openide.actions.RedoAction.performAction(RedoAction.java:71)
        at
org.openide.util.actions.CallableSystemAction$1.run(CallableSystemAction.java:100)
        at
org.netbeans.modules.openide.util.ActionsBridge.doPerformAction(ActionsBridge.java:53)
        at
org.openide.util.actions.CallableSystemAction.actionPerformed(CallableSystemAction.java:96)
        at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
        at
javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
        at
javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
        at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
        at
javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236)
        at java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:272)
        at java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:272)
        at java.awt.Component.processMouseEvent(Component.java:6038)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3260)
        at org.openide.awt.ToolbarButton.processMouseEvent(ToolbarButton.java:39)
        at java.awt.Component.processEvent(Component.java:5803)
        at java.awt.Container.processEvent(Container.java:2058)
        at java.awt.Component.dispatchEventImpl(Component.java:4410)
        at java.awt.Container.dispatchEventImpl(Container.java:2116)
        at java.awt.Component.dispatchEvent(Component.java:4240)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4322)
        at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3986)
        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3916)
        at java.awt.Container.dispatchEventImpl(Container.java:2102)
        at java.awt.Window.dispatchEventImpl(Window.java:2429)
        at java.awt.Component.dispatchEvent(Component.java:4240)
[catch] at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
        at
java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:273)
        at
java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:183)
        at
java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:173)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:168)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:160)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:121)