Margin comments enlarged by zoom... or not

I'm working on two versions of a document. In one, the zoom control changes the size of the marginal comments, as well as the text. In the other, it does not.

What causes this difference? How can I make zoom apply to the marginal comment pane when it does not?

I have cataracts, and until I can have surgery, I need enlarged text to do my work. The marginal comments fixed at 100% scale are unreadable.