Can't see different pages in a layout

[beelia]

In the Printed Output manual, I see an illustration with squares of the four page types clearly visible next to an open page layout.

I cannot see those squares.

Is there something I can toggle to see them? I have several pages in each layout, but can't switch to the right, left, first, etc.

[beelia]

I had to read the entire manual to find the answer to this one. It's the Show Page Overview icon - #7 on the bottom left of the page layout.

It's totally dimmed out when it's not active. You can look at it a zillion times before actually seeing it.