java.lang.NullPointerException
        at org.netbeans.modules.tasklist.usertasks.treetable.DefaultTreeTableModel.setValueAt(DefaultTreeTableModel.java:120)
        at org.netbeans.modules.tasklist.usertasks.treetable.TreeTableModelAdapter.setValueAt(TreeTableModelAdapter.java:203)
        at javax.swing.JTable.setValueAt(JTable.java:2750)
        at javax.swing.JTable.editingStopped(JTable.java:4733)
        at javax.swing.AbstractCellEditor.fireEditingStopped(AbstractCellEditor.java:141)
        at javax.swing.DefaultCellEditor$EditorDelegate.stopCellEditing(DefaultCellEditor.java:368)
        at javax.swing.DefaultCellEditor$3.stopCellEditing(DefaultCellEditor.java:158)
        at javax.swing.DefaultCellEditor.stopCellEditing(DefaultCellEditor.java:233)
        at javax.swing.DefaultCellEditor$EditorDelegate.actionPerformed(DefaultCellEditor.java:385)
        at javax.swing.JComboBox.fireActionEvent(JComboBox.java:1258)
        at javax.swing.JComboBox.actionPerformed(JComboBox.java:1315)
        at javax.swing.DefaultCellEditor$3.stopCellEditing(DefaultCellEditor.java:155)
        at javax.swing.DefaultCellEditor.stopCellEditing(DefaultCellEditor.java:233)
        at javax.swing.plaf.basic.BasicTableUI$Handler.mousePressed(BasicTableUI.java:1013)
        at java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:280)
        at java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:279)
        at java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:279)
        at java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:279)
        at java.awt.Component.processMouseEvent(Component.java:6257)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3309)
        at java.awt.Component.processEvent(Component.java:6025)
        at java.awt.Container.processEvent(Container.java:2083)
        at java.awt.Component.dispatchEventImpl(Component.java:4620)
        at java.awt.Container.dispatchEventImpl(Container.java:2141)
        at java.awt.Component.dispatchEvent(Component.java:4446)
        at java.awt.LightweightDispatcher.retargetMouseEvent(LightweightDispatcher.java:4663)
        at java.awt.LightweightDispatcher.processMouseEvent(LightweightDispatcher.java:4323)
        at java.awt.LightweightDispatcher.dispatchEvent(LightweightDispatcher.java:4256)
        at java.awt.Container.dispatchEventImpl(Container.java:2127)
        at java.awt.Window.dispatchEventImpl(Window.java:2612)
        at java.awt.Component.dispatchEvent(Component.java:4446)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:605)
        at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:117)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:286)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:201)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:191)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:186)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:178)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:139)