java.lang.NullPointerException
        at sun.swing.table.DefaultTableCellHeaderRenderer.getColumnSortOrder(DefaultTableCellHeaderRenderer.java:114)
        at com.sun.java.swing.plaf.windows.WindowsTableHeaderUI$XPDefaultRenderer.getTableCellRendererComponent(WindowsTableHeaderUI.java:108)
        at org.netbeans.modules.tasklist.ui.TaskListTable$SortingHeaderRenderer.getTableCellRendererComponent(TaskListTable.java:702)
        at javax.swing.plaf.basic.BasicTableHeaderUI.getHeaderRenderer(BasicTableHeaderUI.java:663)
        at javax.swing.plaf.basic.BasicTableHeaderUI.getHeaderHeight(BasicTableHeaderUI.java:698)
        at javax.swing.plaf.basic.BasicTableHeaderUI.createHeaderSize(BasicTableHeaderUI.java:727)
        at javax.swing.plaf.basic.BasicTableHeaderUI.getPreferredSize(BasicTableHeaderUI.java:758)
        at javax.swing.JComponent.getPreferredSize(JComponent.java:1632)
        at javax.swing.ViewportLayout.preferredLayoutSize(ViewportLayout.java:78)
        at java.awt.Container.preferredSize(Container.java:1599)
        at java.awt.Container.getPreferredSize(Container.java:1584)
        at javax.swing.JComponent.getPreferredSize(JComponent.java:1634)
        at javax.swing.ScrollPaneLayout.layoutContainer(ScrollPaneLayout.java:702)
        at java.awt.Container.layout(Container.java:1421)
        at java.awt.Container.doLayout(Container.java:1410)
        at java.awt.Container.validateTree(Container.java:1507)
        at java.awt.Container.validateTree(Container.java:1513)
        at java.awt.Container.validateTree(Container.java:1513)
        at java.awt.Container.validateTree(Container.java:1513)
        at java.awt.Container.validateTree(Container.java:1513)
        at java.awt.Container.validateTree(Container.java:1513)
        at java.awt.Container.validateTree(Container.java:1513)
        at java.awt.Container.validateTree(Container.java:1513)
        at java.awt.Container.validateTree(Container.java:1513)
        at java.awt.Container.validate(Container.java:1480)
        at org.netbeans.core.windows.view.ui.DesktopImpl$LayeredLayout.layoutContainer(DesktopImpl.java:466)
        at java.awt.Container.layout(Container.java:1421)
        at java.awt.Container.doLayout(Container.java:1410)
        at java.awt.Container.validateTree(Container.java:1507)
        at java.awt.Container.validateTree(Container.java:1513)
        at java.awt.Container.validateTree(Container.java:1513)
        at java.awt.Container.validateTree(Container.java:1513)
        at java.awt.Container.validateTree(Container.java:1513)
        at java.awt.Container.validate(Container.java:1480)
        at javax.swing.RepaintManager.validateInvalidComponents(RepaintManager.java:670)
        at javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(SystemEventQueueUtilities.java:127)
        at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:597)
        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)