JavaFX 2.2b19
java version "1.7.0_06-ea"
Java(TM) SE Runtime Environment (build 1.7.0_06-ea-b20)
Java HotSpot(TM) 64-Bit Server VM (build 23.2-b09, mixed mode)
Linux linux-jb96 3.1.10-1.16-desktop #1 SMP PREEMPT Wed Jun 27 05:21:40 UTC 2012 (d016078) x86_64 x86_64 x86_64 GNU/Linux

I run several samples from Ensemble application. Fireworks, all media samples (except streaming), graphics 3D audio sample. After Alt+F4 window was closed but application remains running with high CPU usage. I used Ctr+C to terminate application.
Console output attached with hs_err_pid3960.log. Second hs_err_pid4689.log generated without any exceptions on console - (3D audio sample, media samples).

martin@linux-jb96:~/javafx-sdk2.2.0-beta/javafx-samples-2.2.0-beta> java -jar Ensemble.jar
---- FetchDocListTask docsUrl = http://download.oracle.com/javafx/2/api/
Can't create transparent stage, because your screen doesn't support alpha channel. You need to enable XComposite extension.
Exception in runnable
java.lang.NullPointerException
        at javafx.scene.Scene.pick(Scene.java:1702)
        at javafx.scene.Scene.access$6900(Scene.java:169)
        at javafx.scene.Scene$MouseHandler.process(Scene.java:3254)
        at javafx.scene.Scene$MouseHandler.access$8100(Scene.java:3089)
        at javafx.scene.Scene$MouseHandler$1.run(Scene.java:3122)
        at com.sun.javafx.application.PlatformImpl$4.run(PlatformImpl.java:173)
        at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:76)
        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)
^CException in thread "Timer-0" java.lang.IllegalStateException: Attempt to call defer when toolkit not running
        at com.sun.javafx.tk.quantum.QuantumToolkit.defer(QuantumToolkit.java:618)
        at com.sun.javafx.application.PlatformImpl.runLater(PlatformImpl.java:170)
        at com.sun.javafx.application.PlatformImpl.runLater(PlatformImpl.java:148)
        at javafx.application.Platform.runLater(Platform.java:52)
        at javafx.scene.media.MediaTimerTask.run(MediaPlayer.java:2674)
        at java.util.TimerThread.mainLoop(Timer.java:555)
        at java.util.TimerThread.run(Timer.java:505)
#
# A fatal error has been detected by the Java Runtime Environment:
#
# SIGSEGV (0xb) at pc=0x00007f610ce2ead9, pid=3960, tid=140052763416320
#
# JRE version: 7.0_06-b20
# Java VM: Java HotSpot(TM) 64-Bit Server VM (23.2-b09 mixed mode linux-amd64 compressed oops)
# Problematic frame:
# V [libjvm.so+0x70bad9] Monitor::ILock(Thread*)+0x79
#
# Failed to write core dump. Core dumps have been disabled. To enable core dumping, try "ulimit -c unlimited" before starting Java again
#
# An error report file with more information is saved as:
# /home/martin/javafx-sdk2.2.0-beta/javafx-samples-2.2.0-beta/hs_err_pid3960.log
#
# If you would like to submit a bug report, please visit:
# http://bugreport.sun.com/bugreport/crash.jsp
#
Aborted