“Shows when you are playing – not when you are editing”
I’m not sure I understand the chipmunk analogy. The answer to that is “so he can save them for later”. Am I right in interpreting that as “We’re saving showing the CoreGui in Edit mode for a future update”?
Edit: Also, I think it’d be good to clarify that we can edit the CoreGui to change its appearance, see what we select, etc (otherwise the feature would only be half as useful) – it’s just that our changes don’t save to be displayed in online mode, which is perfectly reasonable.
Feel free to Edit CoreGUI while you are playing, yes. Have at it.
Just What You See Is What You Get: when playing is over, CoreGUI goes back to being what it was: your changes do not persist, are not part of your game, etc.