Java Web Start application run on Java SE 8 b79 shows "trust level" SecurityExceptions
intermittently. Once the issue occurs, the error message is repeated:

2013-03-06 13:47:44,203 ERROR [AWT-EventQueue-0] [X.XX.XXX.XXXX.DefaultExceptionHandler] Uncaught Exception: class "X.XX.XXX.XXXX.CannedTreePopup$CannedResponsesDialog$1" does not match trust level of other classes in the same package
java.lang.SecurityException: class "X.XX.XXX.XXXX.CannedTreePopup$CannedResponsesDialog$1" does not match trust level of other classes in the same package
        at com.sun.deploy.security.CPCallbackHandler$ChildElement.checkResource(Unknown Source)
        at com.sun.deploy.security.DeployURLClassPath$JarLoader.checkResource(Unknown Source)
        at com.sun.deploy.security.DeployURLClassPath$JarLoader.getResource(Unknown Source)
        at com.sun.deploy.security.DeployURLClassPath.getResource(Unknown Source)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:357)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:354)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:353)
        at com.sun.jnlp.JNLPClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
        at X.XX.XXX.XXXX.CannedTreePopup$CannedResponsesDialog.<init>(CannedTreePopup.java:1037)
        at X.XX.XXX.XXXX.CannedTreePopup.show(CannedTreePopup.java:623)
        at X.XX.XXX.XXXX.CannedPopupAction.actionPerformed(CannedPopupAction.java:31)
        at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
        at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2346)
        at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
        at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
        at javax.swing.AbstractButton.doClick(AbstractButton.java:376)
        at javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:833)
        at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(BasicMenuItemUI.java:877)
        at java.awt.Component.processMouseEvent(Component.java:6513)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3322)
        at java.awt.Component.processEvent(Component.java:6278)
        at java.awt.Container.processEvent(Container.java:2229)
        at java.awt.Component.dispatchEventImpl(Component.java:4869)
        at java.awt.Container.dispatchEventImpl(Container.java:2287)
        at java.awt.Component.dispatchEvent(Component.java:4691)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4856)
        at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4516)
        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4446)
        at java.awt.Container.dispatchEventImpl(Container.java:2273)
        at java.awt.Window.dispatchEventImpl(Window.java:2721)
        at java.awt.Component.dispatchEvent(Component.java:4691)
        at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:722)
        at java.awt.EventQueue.access$200(EventQueue.java:103)
        at java.awt.EventQueue$3.run(EventQueue.java:681)
        at java.awt.EventQueue$3.run(EventQueue.java:679)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
        at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:86)
        at java.awt.EventQueue$4.run(EventQueue.java:695)
        at java.awt.EventQueue$4.run(EventQueue.java:693)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:692)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:216)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:135)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:123)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:119)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:111)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:97)

At this point the application is broken. Menu item 'File->Exit' does not longer respond.
Likewise, other GUI functions do no longer respond.