[exec] java.lang.IllegalArgumentException: cannot add to layout: unknown constraint: North
     [exec]     at javax.swing.plaf.basic.BasicSplitPaneUI$BasicHorizontalLayoutManager.addLayoutComponent(BasicSplitPaneUI.java:1574)
     [exec]     at javax.swing.plaf.basic.BasicSplitPaneUI$BasicHorizontalLayoutManager.addLayoutComponent(BasicSplitPaneUI.java:1675)
     [exec]     at java.awt.Container.addImpl(Container.java:664)
     [exec]     at javax.swing.JSplitPane.addImpl(JSplitPane.java:1006)
     [exec]     at java.awt.Container.add(Container.java:320)
     [exec]     at javax.swing.plaf.basic.BasicToolBarUI$FrameListener.windowClosing(BasicToolBarUI.java:1097)
     [exec]     at java.awt.Window.processWindowEvent(Window.java:1121)
     [exec]     at javax.swing.JDialog.processWindowEvent(JDialog.java:398)
     [exec]     at java.awt.Window.processEvent(Window.java:1079)
     [exec]     at java.awt.Component.dispatchEventImpl(Component.java:3615)
     [exec]     at java.awt.Container.dispatchEventImpl(Container.java:1627)
     [exec]     at java.awt.Window.dispatchEventImpl(Window.java:1606)
     [exec]     at java.awt.Component.dispatchEvent(Component.java:3477)
     [exec]     at java.awt.EventQueue.dispatchEvent(EventQueue.java:456)
     [exec]     at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:201)
     [exec]     at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)
     [exec]     at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:145)
     [exec]     at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:137)
     [exec]     at java.awt.EventDispatchThread.run(EventDispatchThread.java:100)