I don't like having knowledge of the cheat sheet hard-coded into the generic xblock editor. I don't know enough about how the cheat sheet works, but this seems wrong to me. 

If it has to be done here because there's no alternative, I'd like all the cheat sheet handling logic to be moved out into a separate function to keep it clean. I wouldn't want to see this generic changeMode method become a repository of hacks for different xblocks.