I suspect that this was intentional, but I notice that the debug panel is now no longer accessible when in fullscreen mode.
I'd previously found it vexing that once used, I couldn't hide it in fullscreen, even when 'closed'.
I know that it's not a user feature, but I kind of wish that its visibility could be toggled by repeating 42 in the same way as the camera and map, regardless of fullscreen mode or retaining the 'close' to minimize it to the upper right corner.
I've also noticed that I can use the keyboard shortcuts immediately upon viewer load, as opposed to having to click the synth's photos once first (and thereby unintentionally stopping the slideshow previously).
Oh, and two new keyboard shortcuts:
[F] key = toggle Fullscreen
[Spacebar] key = Pause/Play