[Accordion] Accordion have 2 elements in focus

run this code with jdk1.8 and jfx8.0.
Click on button "Left", then press "Tab" 2 times and you will see that button "right" in focus and "Tile 2" also in focus.
Than press "Shift+Tab" 2 times and in focus will be "Tile1" and "Tile2". You can Click on "Tile1", but "Tile2" still will be in focus.