Here's how I create very erratic behavior with a multi-page document in a two-monitor setup:

1) I take a multi-page document (ideally maybe at least a 6-page document)
2) I put it on my left monitor with a zoom factor of 71% (then I can see three pages at the same time)
3) I create a new window of the same document and put that on the right monitor (with the same zoom)

Problem 1:
4a) I change the zoom factor in the left document with CTRL+mouse wheel and the resolution in the right one changes, too. This is not useful: I want to see each window at the resolution I specify. Just because I zoom into a figure in the let window doesn't mean that in the index on the right I don't want to see three pages anymore!

Problem 2:
4b) I change the zoom factor in the left document with CTRL+mouse wheel and the resolution in the right one changes, too. I then double-click into the the right document and there's always a brief flash in the Writer screen.

Problem 3:
4c) I make the resolution in the left window so large that the page is wider than can be displayed (e.g. 220%). This time, the right window doesn't follow along, but clicking into the left and the right window makes the displayed portions of the windows change erratically.

I am sorry to say but this display thing with more than one window is not done very well. It's not possible to just do what one wants in an intuitive fashion and, I hate to admit it, Word solves all of this much better.