java.lang.NullPointerException
        at org.netbeans.modules.visualweb.propertyeditors.UrlPropertyPanel.generateTargetTree(UrlPropertyPanel.java:389)
        at org.netbeans.modules.visualweb.propertyeditors.UrlPropertyPanel.<init>(UrlPropertyPanel.java:134)
        at org.netbeans.modules.visualweb.propertyeditors.UrlPropertyEditor.getCustomEditor(UrlPropertyEditor.java:105)
        at org.netbeans.modules.visualweb.propertyeditors.binding.ValueBindingPropertyEditor.getCustomEditor(ValueBindingPropertyEditor.java:380)
        at org.openide.explorer.propertysheet.PropertyDialogManager.<init>(PropertyDialogManager.java:129)
        at org.openide.explorer.propertysheet.CustomEditorAction.actionPerformed(CustomEditorAction.java:217)
        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:6134)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3265)
        at java.awt.Component.processEvent(Component.java:5899)
        at java.awt.Container.processEvent(Container.java:2023)
        at java.awt.Component.dispatchEventImpl(Component.java:4501)
        at java.awt.Container.dispatchEventImpl(Container.java:2081)
        at java.awt.Component.dispatchEvent(Component.java:4331)
        at java.awt.LightweightDispatcher.retargetMouseEvent(LightweightDispatcher.java:4299)
        at java.awt.LightweightDispatcher.processMouseEvent(LightweightDispatcher.java:3963)
        at java.awt.LightweightDispatcher.dispatchEvent(LightweightDispatcher.java:3893)
        at java.awt.Container.dispatchEventImpl(Container.java:2067)
        at java.awt.Window.dispatchEventImpl(Window.java:2458)
        at java.awt.Component.dispatchEvent(Component.java:4331)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
        at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:104)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:284)
        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)