Add 2 AnchorPanes, ap1 and ap2.
Add a button to ap1.
Reparent the button to ap2.
If you invoke UNDO, you will get :
Exception in thread "JavaFX Application Thread" java.lang.AssertionError
at com.oracle.javafx.scenebuilder.kit.fxom.FXOMPropertyC.removeFromParentInstance(FXOMPropertyC.java:97)
at com.oracle.javafx.scenebuilder.kit.fxom.FXOMObject.addToParentProperty(FXOMObject.java:65)
at com.oracle.javafx.scenebuilder.kit.editor.job.DeleteObjectJob.undo(DeleteObjectJob.java:61)
at com.oracle.javafx.scenebuilder.kit.editor.job.BatchJob.undo(BatchJob.java:64)
at com.oracle.javafx.scenebuilder.kit.editor.JobManager.undoJob(JobManager.java:144)
at com.oracle.javafx.scenebuilder.kit.editor.JobManager.undo(JobManager.java:81)
at com.oracle.javafx.scenebuilder.kit.editor.EditorController.undo(EditorController.java:492)
at com.oracle.javafx.scenebuilder.app.menubar.MenuBarController$UndoActionController.perform(MenuBarController.java:766)
at com.oracle.javafx.scenebuilder.app.menubar.MenuBarController.handleOnActionMenu(MenuBarController.java:621)
at com.oracle.javafx.scenebuilder.app.menubar.MenuBarController.access$300(MenuBarController.java:48)
at com.oracle.javafx.scenebuilder.app.menubar.MenuBarController$8.handle(MenuBarController.java:614)
at com.oracle.javafx.scenebuilder.app.menubar.MenuBarController$8.handle(MenuBarController.java:610)
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:49)
at javafx.event.Event.fireEvent(Event.java:203)
at javafx.scene.control.MenuItem.fire(MenuItem.java:462)
at com.sun.javafx.scene.control.GlobalMenuAdapter$5.handle(GlobalMenuAdapter.java:158)
at com.sun.javafx.scene.control.GlobalMenuAdapter$5.handle(GlobalMenuAdapter.java:156)
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:203)
at javafx.scene.control.MenuItem.fire(MenuItem.java:462)
at com.sun.javafx.tk.quantum.GlassSystemMenu$6.action(GlassSystemMenu.java:234)