I'm answering my own question. The arrangement tiles appear due to the "Application Window Snap" feature, not the Easy Arrange feature. Once I disabled this, the tiles disappeared.

But now I have a new problem: how do I make a custom layout? I was able to do this with DDM version 1.

* What PC model? HP ZBook Power G7
* What operating system? Windows 10 Pro
* What monitor model? S3422DWG
* How are the two connecting using which ports and cable? Two HDMI inputs from single docking station
* What version of DDM 2.0? The full number like 2.0.0.135: DDM 2.0.0.135

This is confusing = Two HDMI inputs from single docking station

If there is only one HP ZBook Power G7 connected to some unknown dock, are you saying that you are running two HDMI cables from the unknown dock into both HDMI in ports on the S3422DWG?

Remove the unknown dock from the troubleshooting. Connect like this and retest DDM 2.0.0.135 =

HP ZBook Power G7 USB-A port --> S3422DWG USB-A to USB-B cable --> 3422DWG USB-B upstream port

HP ZBook Power G7 HDMI out port --> S3422DWG HDMI to HDMI cable --> S3422DWG #1 HDMI 2.0 in port

HP ZBook Power G7 HDMI out port --> S3422DWG HDMI to HDMI cable --> S3422DWG #2 HDMI 2.0 in port

I have an HP Elite Thunderbolt 3 dock connected to the laptop. This provides two video out ports which I have connected to the two HDMI inputs on the monitor. This allows me to treat the large display as either two independent monitors (useful for sharing one half of the monitor and keeping the other half private), or as one large display if I allow an application to span monitors.

To be clear, I no longer have the issue with the SHIFT key, as I noted in my own response. It was user error; though to be honest, the documentation is not very clear on this topic.

My new issue is that I cannot set up a custom layout. DDM 1.0 allowed me to do this. But I should raise a new thread. This thread can be closed. Thank you for responding.

Test the January 17, 2023 released DDM 2.1.