Exception when expanding nested folders in local view

When in a local project and exploring a directory hierarchy (eg. main directory has 10 subdirectories, each of which have subdirectories) an exception occurs.
A directory structure like so:

root/
root/a/1/
root/a/2/
root/b/1/
root/b/2/

(where Root is the root directory of the project)

It is possible to expand the top-level project but expanding any subfolder results in an exception being logged to stdout and the directory expands simply to a "Loading" entry which never resolves

Platform: Mac OS X 10.6.1
Java: java version "1.6.0_15"
Java(TM) SE Runtime Environment (build 1.6.0_15-b03-219)
Java HotSpot(TM) 64-Bit Server VM (build 14.1-b02-90, mixed mode)

Stack trace:

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at javax.swing.plaf.basic.BasicTreeUI.isToggleEvent(BasicTreeUI.java:2252)
at javax.swing.plaf.basic.BasicTreeUI.selectPathForEvent(BasicTreeUI.java:2317)
at javax.swing.plaf.basic.BasicTreeUI$Handler.handleSelection(BasicTreeUI.java:3525)
at javax.swing.plaf.basic.BasicTreeUI$Handler.mousePressed(BasicTreeUI.java:3464)
at java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:263)
at java.awt.Component.processMouseEvent(Component.java:6345)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3267)
at java.awt.Component.processEvent(Component.java:6113)
at java.awt.Container.processEvent(Container.java:2085)
at java.awt.Component.dispatchEventImpl(Component.java:4714)
at java.awt.Container.dispatchEventImpl(Container.java:2143)
at java.awt.Component.dispatchEvent(Component.java:4544)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4618)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4279)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4212)
at java.awt.Container.dispatchEventImpl(Container.java:2129)
at java.awt.Window.dispatchEventImpl(Window.java:2475)
at java.awt.Component.dispatchEvent(Component.java:4544)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:635)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:296)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:211)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:196)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:188)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)