Get the follow reproduible exception with Java 7 on Windows when running attached designer.zip apps:
 

Exception in thread "AWT-EventQueue-0" java.lang.IllegalArgumentException: Comparison method violates its general contract!
      at java.util.TimSort.mergeHi(TimSort.java:868)
      at java.util.TimSort.mergeAt(TimSort.java:485)
      at java.util.TimSort.mergeCollapse(TimSort.java:410)
      at java.util.TimSort.sort(TimSort.java:214)
      at java.util.TimSort.sort(TimSort.java:173)
      at java.util.Arrays.sort(Arrays.java:659)
      at java.util.Collections.sort(Collections.java:217)
      at javax.swing.SortingFocusTraversalPolicy.enumerateAndSortCycle(SortingFocusTraversalPolicy.java:136)
      at javax.swing.SortingFocusTraversalPolicy.getFocusTraversalCycle(SortingFocusTraversalPolicy.java:110)
      at javax.swing.SortingFocusTraversalPolicy.getFirstComponent(SortingFocusTraversalPolicy.java:435)
      at javax.swing.LayoutFocusTraversalPolicy.getFirstComponent(LayoutFocusTraversalPolicy.java:166)
      at javax.swing.SortingFocusTraversalPolicy.getDefaultComponent(SortingFocusTraversalPolicy.java:515)
      at javax.swing.JComponent.requestDefaultFocus(JComponent.java:2618)
      at sun.swing.SwingUtilities2.tabbedPaneChangeFocusTo(SwingUtilities2.java:1577)
      at javax.swing.JTabbedPane.fireStateChanged(JTabbedPane.java:398)
      at javax.swing.JTabbedPane$ModelListener.stateChanged(JTabbedPane.java:270)
      at javax.swing.DefaultSingleSelectionModel.fireStateChanged(DefaultSingleSelectionModel.java:132)
      at javax.swing.DefaultSingleSelectionModel.setSelectedIndex(DefaultSingleSelectionModel.java:67)
      at javax.swing.JTabbedPane.setSelectedIndexImpl(JTabbedPane.java:616)
      at javax.swing.JTabbedPane.setSelectedIndex(JTabbedPane.java:591)
      at javax.swing.plaf.basic.BasicTabbedPaneUI$Handler.mousePressed(BasicTabbedPaneUI.java:3643)
      at javax.swing.plaf.synth.SynthTabbedPaneUI$1.mousePressed(SynthTabbedPaneUI.java:314)
      at java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:279)
      at java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:279)
      at java.awt.Component.processMouseEvent(Component.java:6501)
      at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)
      at java.awt.Component.processEvent(Component.java:6269)
      at java.awt.Container.processEvent(Container.java:2229)
      at java.awt.Component.dispatchEventImpl(Component.java:4860)
      at java.awt.Container.dispatchEventImpl(Container.java:2287)
      at java.awt.Component.dispatchEvent(Component.java:4686)
      at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4832)
      at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4489)
      at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422)
      at java.awt.Container.dispatchEventImpl(Container.java:2273)
      at java.awt.Window.dispatchEventImpl(Window.java:2713)
      at java.awt.Component.dispatchEvent(Component.java:4686)
      at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:707)
      at java.awt.EventQueue.access$000(EventQueue.java:101)
      at java.awt.EventQueue$3.run(EventQueue.java:666)
      at java.awt.EventQueue$3.run(EventQueue.java:664)
      at java.security.AccessController.doPrivileged(Native Method)
      at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
      at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
      at java.awt.EventQueue$4.run(EventQueue.java:680)
      at java.awt.EventQueue$4.run(EventQueue.java:678)
      at java.security.AccessController.doPrivileged(Native Method)
      at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
      at java.awt.EventQueue.dispatchEvent(EventQueue.java:677)
      at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:211)
      at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:128)
      at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:117)
     at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:113)
      at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:105)
      at java.awt.EventDispatchThread.run(EventDispatchThread.java:90)



Steps to reproduce it:
· double click startDesigner.bat and wait some seconds
· drag the *.rpt file in the root into the desktop pane
· MsgBox --> OK
· Click on the "Result" tab
· Error Box --> ok
· Click on the "Design" tab
· In the console you see the stacktrace of the bug. You can see repeatly the exception if you switch between "Result" tab and "Design" tab.