I agree with Patrick, many people still think it's a good idea to copy the standard programs for doing little changes. This topic has been discussed hundreds of times. I don't know any of good programmers who still want to copy standard programs. You should really stop doing that, and search the forum and you will understand it's now known as a "bad" practice. It's even worse than getting a modification key (although it's often the opposite argument of people pro-copy).
That said, could you show that very complex coding?