java.util.ConcurrentModificationException
   at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:859)
   at java.util.ArrayList$Itr.next(ArrayList.java:831)
   at org.netbeans.api.visual.widget.Widget.paintChildren(Widget.java:1480)
   at org.netbeans.api.visual.widget.Widget.paint(Widget.java:1427)
   at org.netbeans.api.visual.widget.Widget.paintChildren(Widget.java:1481)
   at org.netbeans.api.visual.widget.Widget.paint(Widget.java:1427)
   at org.netbeans.api.visual.widget.SceneComponent.paint(SceneComponent.java:140)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JViewport.paint(JViewport.java:731)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at org.netbeans.swing.tabcontrol.TabbedContainer.paint(TabbedContainer.java:994)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JLayeredPane.paint(JLayeredPane.java:585)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at org.netbeans.core.windows.view.ui.MainWindow$1.paint(MainWindow.java:189)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JLayeredPane.paint(JLayeredPane.java:585)
   at javax.swing.JComponent.paintChildren(JComponent.java:887)
   at javax.swing.JComponent.paint(JComponent.java:1063)
   at javax.swing.JComponent.paintToOffscreen(JComponent.java:5219)
   at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(RepaintManager.java:1529)
   at javax.swing.RepaintManager$PaintManager.paint(RepaintManager.java:1452)
   at javax.swing.RepaintManager.paint(RepaintManager.java:1249)
   at javax.swing.JComponent._paintImmediately(JComponent.java:5167)
   at javax.swing.JComponent.paintImmediately(JComponent.java:4978)
   at javax.swing.JComponent.paintImmediately(JComponent.java:4959)
   at javax.swing.RepaintManager$3.run(RepaintManager.java:808)
   at javax.swing.RepaintManager$3.run(RepaintManager.java:796)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
   at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:796)
   at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:769)
   at javax.swing.RepaintManager.prePaintDirtyRegions(RepaintManager.java:718)
   at javax.swing.RepaintManager.access$1100(RepaintManager.java:62)
   at javax.swing.RepaintManager$ProcessingRunnable.run(RepaintManager.java:1677)
   at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:251)
   at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:733)
   at java.awt.EventQueue.access$200(EventQueue.java:103)
   at java.awt.EventQueue$3.run(EventQueue.java:694)
   at java.awt.EventQueue$3.run(EventQueue.java:692)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
   at java.awt.EventQueue.dispatchEvent(EventQueue.java:703)
   at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:159)
   at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242)
   at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161)
   at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138)
   at java.awt.EventDispatchThread.run(EventDispatchThread.java:91)