I report two problems with zoom when I select a new window on the current document, in LibreOffice 5.4.0.3 x64 Writer on Windows 10.
So, if I select Window > New Window, to get a different view of the document I am working on:
(1) I cannot set a different zoom for that new window. Whatever zoom I select, applies to both windows. This is not how Microsoft Word 2016 behaves.
(2) Moreover, if the zoom is less than Fit width on the second window, the document page is aligned to the left of the screen, instead of being centered, as in the original window.
This behavior is annoying, because it helps me to be able to work on one section of a document (fit width) while having a different section of the document open in another window, with two pages displaying side by side (which is not a problem in Microsoft Word 2016).