Steps to Reproduce: 1. Run the program, and there is some probability to get such an error, but there's no impact on the normal operation. Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: No such child: 68 at java.desktop/java.awt.Container.getComponent(Container.java:350) at java.desktop/javax.swing.JComponent.rectangleIsObscured(JComponent.java:4426) at java.desktop/javax.swing.JComponent.paint(JComponent.java:1072) at java.desktop/javax.swing.JComponent.paintToOffscreen(JComponent.java:5255) at java.desktop/javax.swing.RepaintManager$PaintManager.paintDoubleBufferedFPScales(RepaintManager.java:1707) at java.desktop/javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(RepaintManager.java:1616) at java.desktop/javax.swing.RepaintManager$PaintManager.paint(RepaintManager.java:1556) at java.desktop/javax.swing.RepaintManager.paint(RepaintManager.java:1323) at java.desktop/javax.swing.JComponent._paintImmediately(JComponent.java:5203) at java.desktop/javax.swing.JComponent.paintImmediately(JComponent.java:5013) at java.desktop/javax.swing.RepaintManager$4.run(RepaintManager.java:865) at java.desktop/javax.swing.RepaintManager$4.run(RepaintManager.java:848) at java.base/java.security.AccessController.doPrivileged(AccessController.java:389) at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85) at java.desktop/javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:848) at java.desktop/javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:823) at java.desktop/javax.swing.RepaintManager.prePaintDirtyRegions(RepaintManager.java:772) at java.desktop/javax.swing.RepaintManager$ProcessingRunnable.run(RepaintManager.java:1884) at java.desktop/java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:313) at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:770) at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:721) at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:715) at java.base/java.security.AccessController.doPrivileged(AccessController.java:389) at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85) at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:740) at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203) at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124) at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113) at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109) at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101) at java.desktop/java.awt.EventDispatchThread.run(EventDispatchThread.java:90)