Vertical scrolling in Designer?

This may be an embarrassingly stupid question:
How can I scroll down my page within the Designer view?
I’m not talking about the published version or the site itself, I just want to scroll down when I wok on my site in Designer to see/reach areas or elements further down the page. This is about the WF Designer UI/workflow.
I don’t see any scrollbar (see attached screenshot), and using the keyboard arrows (no matter where the cursor is or what element selected) it just goes down/up the layers in Navigator.
I work with a Wacom tablet and sometimes just with the trackpad on my MacBook. The only way I can scroll down the page right now is by clicking on an element in the Navigator further down the page.
Not practical, but often rather annoying.

What am I missing?

Press shift and mouse scroll