From Vim Tips Wiki
When you are displaying more than one window, you can set the scrollbind option in each window so they scroll together.
In each window that should scroll simultaneously, enter the command:
You can enter
scb as an abbreviation for scrollbind, and the
! flag causes
:set to toggle a boolean option. Therefore, it is convenient to enter the following to toggle scrollbind on or off:
When you scroll a window which has
'scrollbind' set, all other
'scrollbind' windows are scrolled the same amount, if possible.
...and, if your scrollbound windows ever get out of sync, in gvim it's possible to adjust them, as follows: scrolling the current window (by any means) will scroll all scrollbound windows together, but scrolling a non-current window (by means of its scrollbar) won't scroll the other one(s) with it. — Tonymec 00:43, April 4, 2010 (UTC) This technique also works with standard VIM when you have mouse controls enabled and using the mouse-wheel to scroll the inactive window(s).