@Override
    public void start(Stage primaryStage) {
        primaryStage.setTitle("Hello World!");
        HBox root = new HBox(20.0);
        root.getChildren().add(ComboBoxBuilder.create().promptText("Text").editable(true).build());
        primaryStage.setScene(new Scene(root, 300, 250));
        primaryStage.show();
        primaryStage.setTitle(VersionInfo.getRuntimeVersion());
    }

    Run this code - click to combobox for open popup and click again for close popup and press ESC key - output


Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.StackOverflowError
        at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleKeyEvent(GlassViewEventHandler.java:143)
        at com.sun.glass.ui.View.handleKeyEvent(View.java:518)
        at com.sun.glass.ui.View.notifyKey(View.java:951)
        at com.sun.glass.ui.gtk.GtkApplication._runLoop(Native Method)
        at com.sun.glass.ui.gtk.GtkApplication$3$1.run(GtkApplication.java:82)
        at java.lang.Thread.run(Thread.java:722)
Caused by: java.lang.StackOverflowError
        at javafx.event.Event.clone(Event.java:146)
        at javafx.event.Event.copyFor(Event.java:111)
        at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:22)
        at javafx.event.Event.fireEvent(Event.java:171)
        at javafx.scene.Node.fireEvent(Node.java:6772)
        at com.sun.javafx.scene.control.behavior.TextInputControlBehavior.forwardToParent(TextInputControlBehavior.java:359)
        at com.sun.javafx.scene.control.behavior.TextInputControlBehavior.callAction(TextInputControlBehavior.java:165)
        at com.sun.javafx.scene.control.behavior.BehaviorBase.callActionForEvent(BehaviorBase.java:157)
        at com.sun.javafx.scene.control.behavior.TextInputControlBehavior.callActionForEvent(TextInputControlBehavior.java:117)
        at com.sun.javafx.scene.control.behavior.BehaviorBase$1.handle(BehaviorBase.java:121)
        at com.sun.javafx.scene.control.behavior.BehaviorBase$1.handle(BehaviorBase.java:119)
        at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:64)
        at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:217)
        at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:170)
        at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:38)
        at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:37)
        at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
        at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:53)
        at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:28)
        at javafx.event.Event.fireEvent(Event.java:171)
        at javafx.scene.Node.fireEvent(Node.java:6772)
        .....