Split document window or multiple windows on one document?

I often use DT3 to read long PDF documents – book-length documents – in which it would be tremendously helpful to hold one’s place in the text and then open another view elsewhere in the text – to endnotes or an appendix, for example. If DT3 had a feature to allow me to split a window, or open the same document in two different windows and scroll each to different positions in the document (something like Word’s “New Window” function) that would greatly improve usability. I’ve no idea of the impact of such a thing on database internals, but the challenges of scrolling back and forth in a 300-page pdf are enough to make we wish for another method…

In DT3’s script folder.

Wow. I didn’t have that script installed until now. That’s cool. Are the resulting windows full-on windows, that is, you could edit, say, annotations in one and have that reflected in the other…?

Just opening the same document twice in two document windows. The script is a standard script that comes with DT3.

Actually this is an Extra script, from Script menu > more Scripts