Click Caspian button.

node = Accordion@7d1f5ad1[styleClass=accordion] node.lookup(.titled-pane) = null
node = Accordion@1242c7d[styleClass=accordion] node.lookup(.titled-pane) = null
java.lang.IndexOutOfBoundsException: Index: 1, Size: 0
    at java.util.ArrayList.rangeCheck(ArrayList.java:638)
    at java.util.ArrayList.get(ArrayList.java:414)
    at modena.SamplePageHelpers$3.run(SamplePageHelpers.java:279)
    at com.sun.javafx.application.PlatformImpl$5$1.run(PlatformImpl.java:244)
    at com.sun.javafx.application.PlatformImpl$5$1.run(PlatformImpl.java:241)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl$5.run(PlatformImpl.java:241)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
    at com.sun.glass.ui.gtk.GtkApplication._runLoop(Native Method)
    at com.sun.glass.ui.gtk.GtkApplication.access$200(GtkApplication.java:47)
    at com.sun.glass.ui.gtk.GtkApplication$5$1.run(GtkApplication.java:137)
    at java.lang.Thread.run(Thread.java:724)
Exception in thread "JavaFX Application Thread" java.lang.IllegalArgumentException: The owner node needs to be associated with a window
    at javafx.stage.PopupWindow.show(PopupWindow.java:332)
    at javafx.scene.control.ContextMenu.doShow(ContextMenu.java:281)
    at javafx.scene.control.ContextMenu.show(ContextMenu.java:271)
    at modena.SamplePageHelpers$4.run(SamplePageHelpers.java:307)
    at com.sun.javafx.application.PlatformImpl$5$1.run(PlatformImpl.java:244)