Reproduced on b91.

When the content is not set, SwingNode generates awt/swing events which lead to the following exception:

JavaFX Application Thread uncaught: java.lang.IllegalArgumentException
java.lang.IllegalArgumentException: null source
at java.util.EventObject.<init>(EventObject.java:56)
at java.awt.AWTEvent.<init>(AWTEvent.java:337)
at java.awt.event.ComponentEvent.<init>(ComponentEvent.java:120)
at java.awt.event.InputEvent.<init>(InputEvent.java:340)
at java.awt.event.MouseEvent.<init>(MouseEvent.java:736)
at javafx.embed.swing.SwingNode$SwingMouseEventHandler.handle(SwingNode.java:600)
at javafx.embed.swing.SwingNode$SwingMouseEventHandler.handle(SwingNode.java:579)
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.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:202)
at com.sun.javafx.event.EventQueue.fire(EventQueue.java:48)
at javafx.scene.Scene$MouseHandler.handleEnterExit(Scene.java:3548)
at javafx.scene.Scene$MouseHandler.process(Scene.java:3614)
at javafx.scene.Scene$MouseHandler.process(Scene.java:3463)
at javafx.scene.Scene$MouseHandler.access$1900(Scene.java:3415)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1692)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2483)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:312)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:237)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:354)
at com.sun.glass.ui.View.handleMouseEvent(View.java:514)
at com.sun.glass.ui.View.notifyMouse(View.java:877)
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$3$1.run(WinApplication.java:101)
at java.lang.Thread.run(Thread.java:724)



Code to reproduce (mouse over or press key to generate the exceptions):

import javafx.application.Application;
import javafx.embed.swing.SwingNode;
import javafx.scene.Scene;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;

public class SwingNodeEventHandler extends Application {
private SwingNode swingNode;

@Override
public void start(Stage stage) {
StackPane root = new StackPane();
swingNode = new SwingNode();
root.getChildren().add(swingNode);

Scene scene = new Scene(root, 800, 800);
stage.setScene(scene);
stage.show();
}

public static void main(String[] args) {
launch(args);
}
}