Thanks for the reply, eNGiNe.

After playing around with it yesterday, I realized that, by default (at least on my PC), when I click on an insertion in the reviewing pane, it scrolls the main window so that the selected insertion is at the top of the screen unless it is already in view, in which case it just sits there looking dumb, obstinately refusing to tell me where that text is and forcing me to weed through the page manually. That's why I thought that it didn't always find the same text in the main window.

The quasiworkaround I came up with is, if it doesn't scroll somewhere when I click an insertion, scroll the document away from there and try again. Hasn't failed yet.

Still, it would be nice if it would highlight the text in the main document for me and scroll to it, no matter where I am in the document...