I have found that whether extending the display and arrangement is enabled depends on whether the target display is HDMI based or not. Usb-c to VGA based monitor only supports mirroring. This seems a completely artificial limitation. Or can anyone explain why Apple has done this?
There have been several observations from contributors concerning issues with external monitors - and Stage Manager - since updating to iPadOS 16.4.
In absence of documentation that might suggest an intended change to established functionality, issues such as yours are perhaps likely to be unintended - and may therefore be a bug. Here is one such thread:
iPad Extended Desktop not working - Apple Community
As such, you would be best advised to seek assistance directly from Apple Support. You can contact the Support Team using the Support link at top-right or bottom-left of this page. Alternatively and perhaps easier, you can initiate and manage your support cases using the excellent Apple Support App. If not already installed on your iPad, the App can be downloaded from the App Store:
https://apps.apple.com/app/apple-support/id1130498044
You might also consider submitting a Bug Report via Apple’s Product Feedback portal. For iPad and iPadOS:
Just got off the phone with apple support for this same issue: extended display mode not working after upgrading to iPadOS 16.4.1. Spoiler, was able to resolve issue (with caveat that issue might come back, and if it does, I need to let them know).
I found that when plugging into my Sceptre brand dumb-TV with any adapter/dongle/hub the extended display support was not working and the iPadPro would only mirror its display to the TV. We tried plugging my iPadPro into my home office setup, with a Dell WD19DCS dock and Dell P2415Q display, the extended display support worked just fine.
It was suggested to try clearing out the brains on the TV, similar to how you might clear out the SMC on a mac. I then did the following
Turned off the TV
unplugged the TV from the iPadPro
unplugged the TV power cord from the wall outlet
pressed and held the TV power button for greater than 10 seconds
plugged the TV power cord back into the wall outled
Turned on the TV
plugged the TV back into the iPadPro
Then, like magic, extended display support was working just like it was supposed to on the TV. After this I retested it with all my usual hubs and found them all to be working as they had before. The hubs/docks tested were:
ElGato thunderbolt 3 professional dock
Caldigit SoHo dock
Twelve South StayGo hub
Cable Creations usb c hub
Apple Digital AV adapter
Now mind you that this was a very surprising result, as the same docks and TV were still working just fine with a 2017 MacBook Pro, so it didn’t seem like the issue should have been related to the TV. Best we could figure is they just weren’t communicating correctly and resetting the TV made the iPadPro try its handshake a little differently (figuratively speaking). Maybe something was cached weirdly that made it act up after the iPadOS update.
So try resetting the memory on whatever display you are attempting to plug in to and that might just resolve your issue!
iPadOS 16.4 external display only mirroring, no arrangement option with usb-c to VGA
