reorderTiles was programmed to only place a tile in the speaker section if that tile's previous position was off-screen. But for speakers that started off-screen, this would cause them to oscillate in and out of the speaker section on each render, because the speaker section is, of course, on-screen. The solution I've gone with here is to avoid referencing the previous position, and instead go by the computed natural ordering, which ought to be more stable.
