What is the difference between a display header and its more-options chevron?

Clicking a display’s header expands or collapses its entire block. The chevron beneath that block shows or hides additional menu items for the same display. Click the header when you want to hide all items for a display. Click the chevron when you want more options while keeping the main adjustments visible.

The chevron belongs to the section above it. It appears only when that section has additional content to show, so it is different from clicking the next display’s name.

By default, opening another display’s more-options area closes the previous one. See App Menu navigation and menu behavior settings for the available presentation choices.