JFXPanel: Drag and Drop of custom data formats doesn't work.

I tried to add a drag and drop capable javafx control to a swing internal frame.
As long as I use a simple String everythig is fine but unfortuately the drag and drop does not work as I try to use my own custom data format (which is serializeable!!)

The following stackstrace is shown:

onDragDetected
Exception in thread "AWT-EventQueue-0" java.lang.IllegalArgumentException: failed to parse:MyDragAndDropData
at java.awt.datatransfer.DataFlavor.<init>(DataFlavor.java:428)
at javafx.embed.swing.SwingDnD$DnDTransferable.getTransferDataFlavors(SwingDnD.java:458)
at sun.awt.datatransfer.DataTransferer.getFormatsForTransferable(DataTransferer.java:654)
at sun.awt.dnd.SunDragSourceContextPeer.startDrag(SunDragSourceContextPeer.java:129)
at java.awt.dnd.DragSource.startDrag(DragSource.java:321)
at java.awt.dnd.DragSource.startDrag(DragSource.java:426)
at java.awt.dnd.DragGestureEvent.startDrag(DragGestureEvent.java:237)
at javafx.embed.swing.SwingDnD.startDrag(SwingDnD.java:309)
at javafx.embed.swing.SwingDnD.access$1300(SwingDnD.java:71)
at javafx.embed.swing.SwingDnD$4$1.run(SwingDnD.java:261)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:251)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:727)
at java.awt.EventQueue.access$200(EventQueue.java:103)
at java.awt.EventQueue$3.run(EventQueue.java:688)
at java.awt.EventQueue$3.run(EventQueue.java:686)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:697)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:91)
Exception in runnable
java.lang.IllegalArgumentException: Key already associated with a running event loop: java.lang.Object@3b7f4e
at com.sun.javafx.tk.quantum.QuantumToolkit.enterNestedEventLoop(QuantumToolkit.java:514)
at com.sun.javafx.tk.quantum.FxEventLoop$Impl.start(FxEventLoop.java:49)
at com.sun.javafx.tk.quantum.FxEventLoop.enterNestedLoop(FxEventLoop.java:96)
at com.sun.javafx.tk.quantum.EmbeddedSceneDnD$ClipboardAssistanceImpl.flush(EmbeddedSceneDnD.java:167)
at com.sun.javafx.tk.quantum.QuantumClipboard.flush(QuantumClipboard.java:197)
at com.sun.javafx.tk.quantum.QuantumToolkit.startDrag(QuantumToolkit.java:1195)
at javafx.scene.Scene$DnDGesture.dragDetectedProcessed(Scene.java:2652)
at javafx.scene.Scene$DnDGesture.process(Scene.java:2713)
at javafx.scene.Scene$DnDGesture.access$8700(Scene.java:2607)
at javafx.scene.Scene$MouseHandler.process(Scene.java:3344)
at javafx.scene.Scene$MouseHandler.process(Scene.java:3168)
at javafx.scene.Scene$MouseHandler.access$1900(Scene.java:3123)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1563)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2265)
at com.sun.javafx.tk.quantum.EmbeddedScene$2$1.run(EmbeddedScene.java:194)
at com.sun.javafx.tk.quantum.EmbeddedScene$2$1.run(EmbeddedScene.java:176)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.EmbeddedScene$2.run(EmbeddedScene.java:176)
at com.sun.javafx.application.PlatformImpl$4$1.run(PlatformImpl.java:179)
at com.sun.javafx.application.PlatformImpl$4$1.run(PlatformImpl.java:176)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.application.PlatformImpl$4.run(PlatformImpl.java:176)
at com.sun.glass.ui.win.WinApplication._enterNestedEventLoop(Native Method)
at com.sun.glass.ui.Application.enterNestedEventLoop(Application.java:383)
at com.sun.glass.ui.EventLoop.enter(EventLoop.java:83)
at com.sun.javafx.tk.quantum.QuantumToolkit.enterNestedEventLoop(QuantumToolkit.java:520)
at com.sun.javafx.tk.quantum.FxEventLoop$Impl.start(FxEventLoop.java:49)
at com.sun.javafx.tk.quantum.FxEventLoop.enterNestedLoop(FxEventLoop.java:96)
at com.sun.javafx.tk.quantum.EmbeddedSceneDnD$ClipboardAssistanceImpl.flush(EmbeddedSceneDnD.java:167)
at com.sun.javafx.tk.quantum.QuantumClipboard.flush(QuantumClipboard.java:197)
at com.sun.javafx.tk.quantum.QuantumToolkit.startDrag(QuantumToolkit.java:1195)
at javafx.scene.Scene$DnDGesture.dragDetectedProcessed(Scene.java:2652)
at javafx.scene.Scene$DnDGesture.process(Scene.java:2713)
at javafx.scene.Scene$DnDGesture.access$8700(Scene.java:2607)
at javafx.scene.Scene$MouseHandler.process(Scene.java:3344)
at javafx.scene.Scene$MouseHandler.process(Scene.java:3168)
at javafx.scene.Scene$MouseHandler.access$1900(Scene.java:3123)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1563)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2265)
at com.sun.javafx.tk.quantum.EmbeddedScene$2$1.run(EmbeddedScene.java:194)
at com.sun.javafx.tk.quantum.EmbeddedScene$2$1.run(EmbeddedScene.java:176)
at java.security.AccessController.doPrivileged(Native Method) at com.sun.glass.ui.win.WinApplication.access$100(WinApplication.java:29)
at com.sun.glass.ui.win.WinApplication$3$1.run(WinApplication.java:73)
at java.lang.Thread.run(Thread.java:722)
at com.sun.javafx.tk.quantum.EmbeddedScene$2.run(EmbeddedScene.java:176)
at com.sun.javafx.application.PlatformImpl$4$1.run(PlatformImpl.java:179)
at com.sun.javafx.application.PlatformImpl$4$1.run(PlatformImpl.java:176)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.application.PlatformImpl$4.run(PlatformImpl.java:176)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)


When the control is used inside a standalone javafx application, the "drag and drop" works as expected.