JavaFX and Swing on same Thread

On the book "JavaFX- Rich Client Programming on the NetBeans Platform", the authors mentioned the experimental feature to run javafx on the same thread as swing.

I was wondering if anyone got this working.
I tried enabling it with this option in the app.conf:

Code:
 -J-Djavafx.embed.singleThread=true


But I get an exception on startup:


> 	at org.netbeans.core.windows.WindowManagerImpl.warnIfNotInEDT(WindowManagerImpl.java:1770)
> 	at org.netbeans.core.windows.ModeImpl.setBounds(ModeImpl.java:180)
> 	at org.netbeans.core.windows.PersistenceHandler.initModeFromConfig(PersistenceHandler.java:465)
> 	at org.netbeans.core.windows.PersistenceHandler.load(PersistenceHandler.java:204)
> 	at org.netbeans.core.windows.WindowSystemImpl.load(WindowSystemImpl.java:81)
> 	at org.netbeans.core.GuiRunLevel$InitWinSys.run(GuiRunLevel.java:229)
> 	at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
> 	at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:756)
> 	at java.awt.EventQueue.access$500(EventQueue.java:97)
> 	at java.awt.EventQueue$3.run(EventQueue.java:709)
> 	at java.awt.EventQueue$3.run(EventQueue.java:703)
> 	at java.security.AccessController.doPrivileged(Native Method)
> 	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
> 	at java.awt.EventQueue.dispatchEvent(EventQueue.java:726)
> 	at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:159)
> 	at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
> 	at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
> 	at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
> 	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
> 	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
> 	at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
> SEVERE [global]
> java.lang.AssertionError: Window System API is required to be called from AWT thread only, see http://core.netbeans.org/proposals/threading/
> 	at org.netbeans.core.windows.WindowManagerImpl.assertEventDispatchThread(WindowManagerImpl.java:1734)
> 	at org.netbeans.core.windows.ModeImpl.getSelectedTopComponent(ModeImpl.java:312)
> 	at org.netbeans.core.windows.PersistenceHandler.load(PersistenceHandler.java:236)
> 	at org.netbeans.core.windows.WindowSystemImpl.load(WindowSystemImpl.java:81)
> 	at org.netbeans.core.GuiRunLevel$InitWinSys.run(GuiRunLevel.java:229)
> 	at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
> 	at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:756)
> 	at java.awt.EventQueue.access$500(EventQueue.java:97)
> 	at java.awt.EventQueue$3.run(EventQueue.java:709)
> 	at java.awt.EventQueue$3.run(EventQueue.java:703)
> 	at java.security.AccessController.doPrivileged(Native Method)
> 	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
> 	at java.awt.EventQueue.dispatchEvent(EventQueue.java:726)
> 	at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:159)
> [catch] at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
> 	at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
> 	at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
> 	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
> 	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
> 	at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
> 


Looking at the code, it seems SwingUtilities.isEventDispatchThread() is returning false at that point. That's weird, since the stacktrace shows it is on the EDT.

I know this is marked experimental, but why mention it in the book, if it's preventing a netbeans platform app from running? So I'm guessing there must be some way to get this running.