There are scroll-other-window and scroll-other-window-down which are usually bound to M-PgUp and M-PgDown. You can use these to scroll the other window (perhaps

There are scroll-other-window and scroll-other-window-down which are usually bound to M-PgUp and M-PgDown. You can use these to scroll the other window (perhaps another buffer) while the cursor stays in the current one at the same position.