Updating properties on Tooltips / FX Application Thread

Question

Hi all. First post, novice JavaFX developer.
Long story short, I have some nodes on which I've installed tooltips, like so:
tooltip = new Tooltip()
Tooltip.install(node, tooltip)
The node here could be any of a set of graphical elements. Each element then receives the specific tooltip installed on it, like so:
element.setTooltip(tooltip)
The idea is to be able reference this tooltip via the graphical element later and set JavaFX properties on it directly.
So far everything works. However, I'm now trying to update the tooltip text property based on the status received from another, non JavaFX-related part of the application. For updating JavaFX properties in general I have created an updater class that basically reruns its update()-function at a certain frequency. This has been working well for all JavaFX properties I've used so far, but for the tooltip I get the "Not on FX Application Thread" runtime error.
The update()-function is simply initiates a Platform.runLater and loops through my elements, changes JavaFX properties by referencing them directly via the graphical element class they "belong" to. For the tooltip then I would basically do this:
currentTooltip = element.getTooltip()
currentTooltip.setText(text)
This gives "Not on FX Application thread" runtime error. Curiously, the same approach seems to work for all other JavaFX properties I've tried. Say I'm changing the text on a Label instead, I can do this just fine:
currentLabel = element.getLabel()
currentLabel.setText(text)
Or even just element.setLabelText(text) just to "outsource" the actual setting-code to the element itself.
I have two requests.
1. Documentation and examples which can help me better understand the JavaFX Application thread and the boundaries of what I can and can't do to ensure the application runs stable with regards to updating properties "on the fly".
2. Any insight as to why this approach "suddenly" fails for a Tooltip, but works for all other properties I have implemented so far.

Answer 1

I'm not convinced I could reproduce this issue easily in a self-contained class because, well, it is a little more complicated than this.
Because the JavaFX part has to live within a Swing-based application, the panel which contains the JavaFX GUI is a TopComponent. The updater in question is at it's core a simple extension of SwingWorker (http://docs.oracle.com/javase/6/docs/api/javax/swing/SwingWorker.html). A separate class implements overrides to the doInBackground() and process() methods, passing through the updater, which is in turn basically just a Platform.runLater block containing all the specific code that checks for application state and sets properties. It should be fairly straightforward, and has been well tested with other JavaFX properties and shown to work.
The updater code itself is simply this.
Platform.runLater {
updateSomething
updateSomethingElse
andSoOn
The trace is as follows.
java.lang.IllegalStateException: Not on FX application thread; currentThread = AWT-EventQueue-0
     at com.sun.javafx.tk.Toolkit.checkFxUserThread(Toolkit.java:239)
     at com.sun.javafx.tk.quantum.QuantumToolkit.checkFxUserThread(QuantumToolkit.java:392)
     at javafx.scene.Scene.<init>(Scene.java:286)
     at javafx.scene.Scene.<init>(Scene.java:194)
     at javafx.stage.PopupWindow.<init>(PopupWindow.java:102)
     at javafx.scene.control.PopupControl.<init>(PopupControl.java:98)
     at javafx.scene.control.Tooltip.<init>(Tooltip.java:133)
As you can see, the thread that tries to update the Tooltip is actually the AWT EventQueue, which puzzles me to no end. Probably something to do with the symbiosis between the SwingWorker thread and the JavaFX Application thread, but these things are a nightmare to debug at the best of times ...