java.lang.NullPointerException
        at org.netbeans.modules.xml.schema.model.impl.SchemaComponentImpl.populateChildren(SchemaComponentImpl.java:101)
        at org.netbeans.modules.xml.xam.AbstractComponent._getChildren(AbstractComponent.java:154)
        at org.netbeans.modules.xml.xam.AbstractComponent.getChildren(AbstractComponent.java:138)
        at org.netbeans.modules.xml.schema.model.visitor.DeepSchemaVisitor.visitChildren(DeepSchemaVisitor.java:266)
        at org.netbeans.modules.xml.schema.model.visitor.DeepSchemaVisitor.visit(DeepSchemaVisitor.java:54)
        at org.netbeans.modules.xml.schema.model.impl.LocalSimpleTypeImpl.accept(LocalSimpleTypeImpl.java:76)
        at org.netbeans.modules.xml.axi.impl.AXIModelBuilderQuery.affectsModel(AXIModelBuilderQuery.java:98)
        at org.netbeans.modules.xml.axi.impl.SchemaModelListener.isValidEvent(SchemaModelListener.java:107)
        at org.netbeans.modules.xml.axi.impl.SchemaModelListener.propertyChange(SchemaModelListener.java:77)
        at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:339)
        at org.netbeans.modules.xml.xam.AbstractModel$Transaction.fireCompleteEventSet(AbstractModel.java:488)
        at org.netbeans.modules.xml.xam.AbstractModel$Transaction.fireEvents(AbstractModel.java:474)
        at org.netbeans.modules.xml.xam.AbstractModel.endTransaction(AbstractModel.java:321)
        at org.netbeans.modules.xml.xam.AbstractModel.endTransaction(AbstractModel.java:313)
        at org.netbeans.modules.xml.xam.ui.customizer.AbstractComponentCustomizer.apply(AbstractComponentCustomizer.java:93)
        at org.netbeans.modules.xml.schema.ui.basic.UIUtilities$2.actionPerformed(UIUtilities.java:257)
        at org.netbeans.core.windows.services.NbPresenter$ButtonListener.actionPerformed(NbPresenter.java:1139)
        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.Component.processMouseEvent(Component.java:6216)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3265)
        at java.awt.Component.processEvent(Component.java:5981)
        at java.awt.Container.processEvent(Container.java:2041)
        at java.awt.Component.dispatchEventImpl(Component.java:4583)
        at java.awt.Container.dispatchEventImpl(Container.java:2099)
        at java.awt.Component.dispatchEvent(Component.java:4413)
        at java.awt.LightweightDispatcher.retargetMouseEvent(LightweightDispatcher.java:4556)
        at java.awt.LightweightDispatcher.processMouseEvent(LightweightDispatcher.java:4220)
        at java.awt.LightweightDispatcher.dispatchEvent(LightweightDispatcher.java:4150)
        at java.awt.Container.dispatchEventImpl(Container.java:2085)
        at java.awt.Window.dispatchEventImpl(Window.java:2475)
        at java.awt.Component.dispatchEvent(Component.java:4413)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
        at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:104)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:178)
        at java.awt.Dialog$1.run(Dialog.java:1051)
        at java.awt.Dialog$3.run(Dialog.java:1103)
        at java.security.AccessController.doPrivileged(AccessController.java:0)
        at java.awt.Dialog.show(Dialog.java:1101)
        at org.netbeans.core.windows.services.NbPresenter.superShow(NbPresenter.java:867)
        at org.netbeans.core.windows.services.NbPresenter.doShow(NbPresenter.java:901)
        at org.netbeans.core.windows.services.NbPresenter.run(NbPresenter.java:889)
        at org.netbeans.core.windows.services.NbPresenter.run(NbPresenter.java:109)
        at org.openide.util.Mutex.doEventAccess(Mutex.java:1355)
        at org.openide.util.Mutex.readAccess(Mutex.java:268)
        at org.netbeans.core.windows.services.NbPresenter.show(NbPresenter.java:874)
        at java.awt.Component.show(Component.java:1516)
        at java.awt.Component.setVisible(Component.java:1468)
        at java.awt.Window.setVisible(Window.java:841)
        at java.awt.Dialog.setVisible(Dialog.java:991)
        at org.openide.explorer.propertysheet.CustomEditorAction.actionPerformed(CustomEditorAction.java:318)
        at org.openide.explorer.propertysheet.SheetTable.processMouseEvent(SheetTable.java:710)
        at java.awt.Component.processEvent(Component.java:5981)
        at java.awt.Container.processEvent(Container.java:2041)
        at java.awt.Component.dispatchEventImpl(Component.java:4583)
        at java.awt.Container.dispatchEventImpl(Container.java:2099)
        at java.awt.Component.dispatchEvent(Component.java:4413)
        at java.awt.LightweightDispatcher.retargetMouseEvent(LightweightDispatcher.java:4556)
        at java.awt.LightweightDispatcher.processMouseEvent(LightweightDispatcher.java:4217)
        at java.awt.LightweightDispatcher.dispatchEvent(LightweightDispatcher.java:4150)
        at java.awt.Container.dispatchEventImpl(Container.java:2085)
        at java.awt.Window.dispatchEventImpl(Window.java:2475)
        at java.awt.Component.dispatchEvent(Component.java:4413)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
        at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:104)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)