catalinadisplayipadmacossidecar
I have an iPad Pro (2018 3rd Gen) that I'm using as 2nd display with my Macbook Pro (2018). I can enable it and it works well, but it's on the wrong side of my Macbook and there's no options in Sidecar to change the display arrangement.
How do I change the monitor arrangement of my iPad relative to my Macbook?
Update: There are now several competitors, such as Luna Display, as well as native support in iPadOS 13 + macOS Catalina, called Sidecar.
The app Duet Display lets iOS devices connect to a Mac that is running at least OS 10.9. The Mac needs duet software which is a free download and connects via Lightning port to the Mac in question to send the video.
The Mac app is a free download and the iOS app is available for purchase on the iOS App Store.
You will need an app to get this working properly, the nice new features in Mavericks are still essentially limited to traditionally connected displays via cables (DisplayPort/HDMI/Thunderbolt), rather than wireless connections. There are many you can try, but my (unaffiliated merely personal preference) recommendation is Air Display.
Note that because the 2nd screen will be transferred over Wifi, you need to ensure that the iPad has a solid connection to the same LAN as your main Mac - being close to your Mac might be no good if they are both a distance away from the router... As such, any usage of the iPad 2nd screen that requires fast refresh of window contents might not perform in any way like a proper monitor would, but it should be great for normal non video/gaming OS X apps.
Best Answer
Sidecar has no settings to change monitor arrangement. You only enable the iPad as an additional display in the Mac's System Preferences. You still have to go to "Displays" in your Mac's System Prefs to change the arrangement of the iPad as a display relative to your Mac.
After (2) days of dragging things in the opposite direction to the iPad display it finally occurred to me to check Displays... D'Oh!