I have legacy content that has line breaks as paragraph separator. When trying to deal with them using CKEditor module 7.x-1.16 and CKEditor 4.5.4 library, all line breaks are removed and the text turned into an ugly mass of text.
I tried disabling some filters from the Full HTML input format:
Limit allowed HTML tags
Convert line breaks into HTML
Correct faulty and chopped off HTML
I also tried to use custom formatting options and disabling _Advanced content filter. In any case, I didn't achieve my purpose.