NullPointer exception when clicking relation in property editor

[smsm1]

Early in the editing session, I could edit relations fine, now they just give the following error message when I click a relation in the property editor.

Repository Root: ​http://josm.openstreetmap.de/svn
Build-Date: 2010-04-24 01:31:33
Last Changed Author: stoecker
Revision: 3201
Repository UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
URL: ​http://josm.openstreetmap.de/svn/trunk
Last Changed Date: 2010-04-23 23:09:20 +0200 (Fri, 23 Apr 2010)
Last Changed Rev: 3201

Memory Usage: 669 MB / 1018 MB (275 MB allocated, but free)
Java version: 1.6.0_17, Apple Inc., Java HotSpot(TM) 64-Bit Server VM
Operating system: Mac OS X

Dataset consistency test:
No problems found

Plugins: AddrInterpolation,buildings_tools,graphview,openstreetbugs,photo_geotagging,remotecontrol,routing,slippymap,tageditor,terracer,turnrestrictions,validator,wmsplugin
Plugin openstreetbugs (Version: 20696)
Plugin tageditor (Version: 20530)
Plugin validator (Version: 20799)
Plugin slippymap (Version: 19887)
Plugin routing (Version: 19475)
Plugin graphview (Version: 19441)
Plugin AddrInterpolation (Version: 19422)
Plugin terracer (Version: 20956)
Plugin photo_geotagging (Version: 19873)
Plugin turnrestrictions (Version: 20745)
Plugin wmsplugin (Version: 20891)
Plugin remotecontrol (Version: 19946)
Plugin buildings_tools (Version: 20269)

java.lang.NullPointerException

at org.openstreetmap.josm.gui.dialogs.properties.PropertiesDialog$10.getTableCellRendererComponent(PropertiesDialog.java:501)
at javax.swing.JTable$AccessibleJTable.getAccessibleChild(JTable.java:7032)
at javax.swing.JTable$AccessibleJTable.getAccessibleAt(JTable.java:7419)
at javax.swing.JTable$AccessibleJTable.valueChanged(JTable.java:6934)
at javax.swing.DefaultListSelectionModel.fireValueChanged(DefaultListSelectionModel.java:167)
at javax.swing.DefaultListSelectionModel.fireValueChanged(DefaultListSelectionModel.java:147)
at javax.swing.DefaultListSelectionModel.fireValueChanged(DefaultListSelectionModel.java:194)
at javax.swing.DefaultListSelectionModel.changeSelection(DefaultListSelectionModel.java:388)
at javax.swing.DefaultListSelectionModel.changeSelection(DefaultListSelectionModel.java:398)
at javax.swing.DefaultListSelectionModel.setSelectionInterval(DefaultListSelectionModel.java:442)
at javax.swing.JTable.changeSelectionModel(JTable.java:2351)
at javax.swing.JTable.changeSelection(JTable.java:2420)
at javax.swing.plaf.basic.BasicTableUI$Handler.adjustSelection(BasicTableUI.java:1085)
at javax.swing.plaf.basic.BasicTableUI$Handler.mousePressed(BasicTableUI.java:1008)
at javax.swing.plaf.basic.BasicTableUI$MouseInputHandler.mousePressed(BasicTableUI.java:768)
at com.apple.laf.AquaTableUI$MouseInputHandler.mousePressed(AquaTableUI.java:73)
at java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:263)
at java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:262)
at java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:262)
at java.awt.Component.processMouseEvent(Component.java:6345)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3255)
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)

[stoecker]

Do you have an example dataset? Can you reproduce this issue?