Design mode and Mutate Sidechanges shouldn't be shown in puzzles where one can't use them.
That makes it easier for beginners as they don't have to wonder about how the can use them in the puzzle.

The same goes for Align Guide. Before doing my first puzzle with a guide I didn't understand what it was about and there's no need to have that button in puzzles without a guide. It's similar to the introduction puzzles where only the tools get shown that can be used.