Was teased out of RT-29776, the problem is that the Task / Service do thread checks and throw an exception if you tried to use them from a thread other than the FX thread. The problem with this is that you can't use Task or Service when setting up your GUI in the init method which is bad because it means:
    - You can't kick off any tasks until the FX thread is fired up
    - You can't create any tasks and wire them up to JavaFX UI, so you have to create the UI in init and then wire it up in startup which is bad