I have this code in start method:

        Accordion accordion = new Accordion();
        accordion.setStyle("-fx-background-color: #FF0000");
        
        accordion.getPanes().add(new TitledPane("1", new AnchorPane()));
        accordion.getPanes().add(new TitledPane("2", new AnchorPane()));
        accordion.getPanes().add(new TitledPane("3", new AnchorPane()));
        accordion.getPanes().add(new TitledPane("4", new AnchorPane()));
        
        Button remove = new Button("remove");
        remove.setOnAction((event) -> {
            if (accordion.getPanes().size() != 0)
                accordion.getPanes().remove(0);
        });

        VBox vBox = new VBox(accordion, remove);
        VBox.setVgrow(remove, Priority.ALWAYS);
        
        Scene scene = new Scene(vBox);
        primaryStage.setScene(scene);
        primaryStage.show();


Steps to exception:
1) Expand pane "4" (or any other pane);
2) Click remove 4 times (remove all panes);
3) Click on red area;

Stack trace:
Exception in thread "JavaFX Application Thread" java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
at java.util.ArrayList.rangeCheck(ArrayList.java:638)
at java.util.ArrayList.get(ArrayList.java:414)
at com.sun.javafx.collections.ObservableListWrapper.get(ObservableListWrapper.java:87)
at com.sun.javafx.scene.control.behavior.AccordionBehavior$AccordionFocusModel$1.changed(AccordionBehavior.java:170)
at com.sun.javafx.scene.control.behavior.AccordionBehavior$AccordionFocusModel$1.changed(AccordionBehavior.java:160)
at com.sun.javafx.binding.ExpressionHelper$Generic.fireValueChangedEvent(ExpressionHelper.java:347)
at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:80)
at javafx.beans.property.ReadOnlyBooleanPropertyBase.fireValueChangedEvent(ReadOnlyBooleanPropertyBase.java:72)
at javafx.scene.Node$FocusedProperty.notifyListeners(Node.java:7486)
at javafx.scene.Scene$15.invalidated(Scene.java:2076)
at javafx.beans.property.ObjectPropertyBase.markInvalid(ObjectPropertyBase.java:111)
at javafx.beans.property.ObjectPropertyBase.set(ObjectPropertyBase.java:145)
at javafx.scene.Scene$KeyHandler.setFocusOwner(Scene.java:3910)
at javafx.scene.Scene$KeyHandler.requestFocus(Scene.java:3956)
at javafx.scene.Scene$KeyHandler.access$2200(Scene.java:3896)
at javafx.scene.Scene.requestFocus(Scene.java:2040)
at javafx.scene.Node.requestFocus(Node.java:7647)
at com.sun.javafx.scene.control.behavior.AccordionBehavior.mousePressed(AccordionBehavior.java:152)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:95)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:89)
at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
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.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
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.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
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 javafx.scene.Scene$MouseHandler.process(Scene.java:3746)
at javafx.scene.Scene$MouseHandler.access$1800(Scene.java:3471)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1695)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2486)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:314)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:243)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:345)
at com.sun.glass.ui.View.handleMouseEvent(View.java:526)
at com.sun.glass.ui.View.notifyMouse(View.java:898)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.access$300(WinApplication.java:39)
at com.sun.glass.ui.win.WinApplication$4$1.run(WinApplication.java:112)
at java.lang.Thread.run(Thread.java:745)