Rows in the product list that have a picture carry a small square control at the end of the row. Choosing it prints that section's interface in the margin to the right of the list, where the note already appears, and it stays there until another is chosen. The first one in each group is showing when the page loads. Nothing opens, expands or moves: the margin already reserves the space, and pointing at a row still just shows the note. Every picture is drawn in the page itself rather than being a screenshot, so it stays sharp at any size. The margin appears on wide windows only, as the notes do. Meetings is the first section drawn; more are coming.
See what a section looks like from the product list
The front page prints a picture of a section's interface in the margin beside the list.