This confused me at first, which is why I am putting it here. It appears that you cannot put formatting things inside pieces of code. I can't show you what I mean becuase they change the text. While I am not an expert, I know that they look like HTML "tags", or at least I think that is what they are called. Here is an example
It appears to only be with code tag things, or at least it does not happen with quote or size ones.