Resposta curta:
Press Command-F1 to toggle to multiple displays.
Esta é a resposta longa que recebi da empresa que exibe ar:
Unfortunately you're running into a known bug in Sierra's Displays preference pane. We believe this bug affects all virtual displays, not just Air Display. We've reported the bug to Apple and hope have been hoping that they are able to fix it in a near-term macOS software update. A few days ago, I got an email saying that the bug I reported has been closed. There's no way to tell whether that means it has been closed with a disposition of "Fixed" or "Will Not Fix" or "Not a Bug." But we're hopeful that it's going to be fixed in macOS 10.12.3, which is in beta now.
Meanwhile, while you can't rearrange the monitor placements, you can toggle between Mirroring and Screen Extension modes by pressing Command-F1. (Depending on your Keyboard settings, you may have to hold down the Fn key at the same time.)
Apple is aware of this issue with bug report: <rdar://28888038>.