text editor removed all line breaks in file

Hi again ??

I just experienced something new. I used filezilla to edit a functions.php and used notepadd++ as my editor. When I uploaded the changes the site broke. After a minute of trying to figure it out, I opened a fresh copy of the file and all the line breaks had been removed. Using the same editor I manually went through the file putting line breaks where they needed to be and it fixed the problem.

So, my question is, Is there a particular editor the original developer might have used like regular notepad that would have caused this problem when saving with notepadd++?

I am afraid to open any other files till I figure this out.

Thanks