How do you scroll said document on the screen? Do you do it one line at a time, show a whole page, keep current line at the top, bottom? There's such a myriad o

How do you scroll said document on the screen? Do you do it one line at a time, show a whole page, keep current line at the top, bottom? There's such a myriad of issues and challenges associated with document scrolling etiquette, IMO.