What’s the scroll lock key actually for?
Scroll Lock was reportedly specifically added for spreadsheets, and it solved a very specific problem: before mice and trackpads, and before fast graphic cards, moving through a spreadsheet was a nightmare. Just like Caps Lock flipped the meaning of letter keys, and Num Lock that of the numeric keypad keys, Scroll Lock attempted to fix scrolling by changing the nature of the arrow keys.
↫ Marcin Wichary
I never really put much thought into the scroll lock key, and I always just assumed that it would, you know, lock scrolling. I figured that in the DOS era, wherein the key originated, it stopped DOS from scrolling, keeping the current output of your DOS commands on the screen until you unlocked scrolling again. In graphical operating systems, I assumed it would stop any window with scrollable content from scrolling, or something – I just never thought about it, and never bothered to try.
Well, its original function was a bit different: with scroll lock disabled, hitting the arrow keys would move the selection cursor. With scroll lock enabled, hitting the arrow keys would move the content instead. After reading this, it makes perfect sense, and my original assumption seems rather silly. It also seems some modern programs, like Excel, Calc, some text editors, and others, still exhibit this same behaviour when the scroll lock key is used today.
The more you know.
