Mutate Tool isn't working?

[adragonsfire]

I've just started and am working through the beginner puzzles. I've reached the one that is meant to teach me how to use the mutate tool and the mutate tool's menu simply will not open. It could be an issue related to my computer/touchpad setup but is there a known fix for this?

[rmoretti]

If you're talking about the "Intro to Design" puzzle, you need to select which residue you want to mutate first (left click on it), and then click the M button to mutate that residue.