i have no idea how to title this.

this is not that much of a bug as it is an oversight.

The book's desciption of the looking glass tells you to press "sneak" to move the cursor even though it requires you to press "SHIFT" instead.

never use the name of a default keybind if you are not going to directly use the key bound to it. this is a great example of that, saying to press sneak but not setting it so that it uses whatever key is bound to sneak it can lead to problems where players think the mod or game broke because pressing their rebound sneak doesn't do anything...

so you could either rewrite the book to say SHIFT instead of sneak, or make it actually use the key bound to sneak.