Run the following code:

        stage.fullScreenProperty().addListener(new InvalidationListener()
        {
            @Override
            public void invalidated(Observable observable)
            {
                if (!stage.isFullScreen()) {
                    stage.close();
                }
            }
        });

It causes NPE thrown from GlassViewEventHandler:

java.lang.IllegalStateException: The view has already been closed
at com.sun.glass.ui.View.checkNotClosed(View.java:393)
at com.sun.glass.ui.View.getX(View.java:421)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleViewEvent(GlassViewEventHandler.java:548)
at com.sun.glass.ui.View.handleViewEvent(View.java:495)
at com.sun.glass.ui.View.handleViewEvent(View.java:824)
at com.sun.glass.ui.win.WinView._exitFullscreen(Native Method)
at com.sun.glass.ui.View.exitFullscreen(View.java:763)
at com.sun.javafx.tk.quantum.WindowStage.applyFullScreen(WindowStage.java:510)
at com.sun.javafx.tk.quantum.WindowStage.setFullScreen(WindowStage.java:539)
at com.sun.javafx.tk.quantum.WindowStage.exitFullScreen(WindowStage.java:463)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleKeyEvent(GlassViewEventHandler.java:111)
at com.sun.glass.ui.View.handleKeyEvent(View.java:502)
at com.sun.glass.ui.View.notifyKey(View.java:936)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.access$100(WinApplication.java:29)
at com.sun.glass.ui.win.WinApplication$2$1.run(WinApplication.java:62)
at java.lang.Thread.run(Thread.java:722)