I've read several solutions to this problem, all of which seem to involve looking for a key in the registry at
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\GraphicsDrivers\Configuration, which is prefixed with
SIMULATED_. I have no such key in there. I only have two keys: One that represents two of my 3 monitors, and another that represents all three.
I tried deleting everything in
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\GraphicsDrivers\Configuration and in
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\GraphicsDrivers\Connectivity and rebooted. This reset my monitor settings, and I had to re-arrange the desktops accordingly... but the problem still comes up now and again.
I've noticed just now that when I woke the monitors, my center monitor was set to a resolution of 1920x1080 while the side monitors were 2560x1440. So somehow, the resolution is getting changed at random, and (most of the time) it gets reverted back, thus causing the shift in windows.
A few other times, I've noticed that all my desktop icons have been moved to another screen (I keep them in the center) despite the center screen being the "primary" in Windows. So here, it seems, two monitors just randomly swapped places in settings.
Here's a screenshot of my relevant registry settings. I've selected one of the registry keys, but the other two below are the exact same, it seems.
I have three ASUS PB278Q monitors (27 inch 2560x1440) and I've been having problems ever since I upgraded from Windows 8.1 to Windows 10 last year. I often pin two specific windows next to eachother on one monitor, and when I come back to my computer after a long period of time, I find that sometimes (but not all the time) the windows are not positioned correctly anymore. They are on the same monitor, but it's as if the resolution changed overnight and now the windows are not where they were.
On one of my other monitors, I find that sometimes (but again, not always) the windows completely move to my center monitor.
My left-most monitor is connected via Dual Link DVI, while the middle (primary) and right monitors are connected via DisplayPort.
DDC/CI is enabled for all three monitors.
I have a NVidia GTX 960 with fairly recent (if not newest) drivers.