Here's a pretty simple improvement you could make to the new theme. One pet peeve of mine has been the play button; I've never liked the fact that you press the play button icon again to exit play mode. It just doesn't feel intuitive or correct. Now I guess this was originally meant to imitate how physical buttons function, but as far as I know, all physical play buttons are not toggle-able and always accompanied by a separate stop button. Pressing a depressed button doesn't make any sense to me anyway. Isn't that physically impossible? In any case, this new flat theme has removed any rationale the original design may have had, since we're not imitating physical elements anymore. The now slightly shaded flat button is almost indistinguishable from it's normal state. Making the state change almost unnoticeable. Now you could fix this by adding some depth to the button again but I've always thought that the play icon should actually change into a stop icon when in play mode to make it's changed functionality much more obvious. I think this tiny change would be a vast improvement since it makes the play state and buttons changed purpose much more obvious. This should also help remind users they're in play mode.