Scrolling affects multiple documents at once

When I have multiple Pages documents open, and I scroll (two finger) the document at the front, I can see that the Pages document behind it is also scrolling at the same time. This also makes the front document's scrolling both sluggish and jumpy, and it stops scrolling as soon as I lift my fingers, instead of gliding as it normally does.

Very annoying, not only for navigating my front document, but also because when I witch back to my other document it's no longer on the page where I left it.