If you are used to using it, then it should not have gotten out of hand like I am theorizing it did -- if it did!
You can always try a sandboxed effort of applying the CC646 edits of the new code to a copy of that file from CC645 and see if it happens again. If you have a mind to.
Good reviews about Notepad++. (I don't use it because it doesn't do a few things I find very useful.)