Hello,
I am working with Canvas and GraphicsContext in JavaFX 2.2, and only on the windows platform there is a strange render bug, where the canvas content would weirdly go over only some of the other controls in the scene, although it's set to be in the background.
Here's an imgur album of the error:
JavaFX render bug - Imgur
(note that the maps in the 2 screenshots are different, so that is not the error in question, just the weird overlay)