When invoking unwrap (from arrange menu or contextual) on a BorderPane, you get :

at com.oracle.javafx.scenebuilder.kit.editor.job.wrap.WrapJobUtils.canUnwrap(WrapJobUtils.java:152)
at com.oracle.javafx.scenebuilder.kit.editor.job.wrap.UnwrapJob.isExecutable(UnwrapJob.java:78)
at com.oracle.javafx.scenebuilder.kit.editor.EditorController.canPerformEditAction(EditorController.java:1259)
at com.oracle.javafx.scenebuilder.app.menubar.MenuBarController$EditActionController.canPerform(MenuBarController.java:1547)
at com.oracle.javafx.scenebuilder.app.menubar.MenuBarController.handleOnMenuValidation(MenuBarController.java:1067)
at com.oracle.javafx.scenebuilder.app.menubar.MenuBarController.access$700(MenuBarController.java:90)
at com.oracle.javafx.scenebuilder.app.menubar.MenuBarController$19.handle(MenuBarController.java:1055)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
at javafx.event.Event.fireEvent(Event.java:204)
at com.sun.javafx.scene.control.GlobalMenuAdapter$MenuItemAdapter.fireValidation(GlobalMenuAdapter.java:193)
at com.sun.javafx.tk.quantum.GlassSystemMenu$6.validate(GlassSystemMenu.java:243)