I had such a problem. When Windows sends monitors to sleep state or monitor is powered off, monitors on DisplayPort connections send hot-plug event and are removed from the system. Windows then moves windows and icons onto remaining monitors.

NVIDIA firmware update [0] solved the problem for me. It seems they ditched the naughty part of DisplayPort standard for good and stopped passing hot-plug events to OS.

[0]: https://www.nvidia.com/object/nv-uefi-update-x64.html

This did not help in my case. I have 3 DisplayPort 1.2 monitors, and half of the open windows get still tossed around randomly when the monitors wake from sleep, or when the whole PC wakes from sleep.

I'm in the same boat with my Dell P2210t- it's DisplayPort connection "disconnects" the screen, which is really annoying when you're trying to operate remotely and your config doesn't match its anymore.

A couple years ago the other option was to dump the EDID of the connected monitor (while it was on of course) using Nvidia's display software and then set the EDID data using the same software (overriding the EDID which would apparently get cleared when the monitor sent its hotplug event). If you ever actually removed the monitor you'd have to go remove the EDID data.

I think it depends on the connection you use. If I turn off one of my monitors connected via DisplayPort, Windows 10 immediately moves everything to the monitors that are still on. My last computer, with monitors connected via DVI did not do this.

I actually wish my laptop did this. I constantly have issues with some windows staying open on the second monitor after unplugging them both from my laptop.

Sometimes I can't get to them at all on the laptop screen without forcing it closed and reopening.

FYI in Windows if you can give the correct window focus (via taskbar or alt-tab) you can move them between screens with [win] + [shift] + [left/right arrow].

The regular [win] + [left/right] for snapping to 1/2 screen positions will also move it across screens if you hit it repeatedly.

Alternately the old-school variation (works since at least Windows 3.11): [alt] + [space] to open upper-left corner menu, [m] to move, then [arrow keys] to move the window around.

Once you've started this process, I believe you can just move the mouse (without clicking) to move the window as well. This tends to be faster than using the arrow keys, especially at modern display resolutions.

this is the workaround I use but it's super annoying. I have two displays at work but I switch the second one between two different computers. inevitably windows will remember the last location of some modal dialog and spawn it on the disconnected monitor, blocking the main application until I figure out whether it froze or there's a hidden dialog window on the other screen.

That's a Windows OS issue and it drives me crazy too, I raised an issue for it on the official Windows 10 feedback site, will try to find & post the link for it later, can't right now...

My most popular SuperUser question[0] (as well as Googling) revealed that many people have this problem with DisplayPort connections in Windows 7/10, although Windows 10 seems to have patched the problem to some degree with a relatively recent update (within the last couple months) - my icons are still moved to HDMI monitors when disabling a DP monitor, but positions are restored as long as I turn on all DP monitors in rapid succession... and in the correct order.

[0]: https://superuser.com/questions/630555/turning-displayport-m...

pre windows 10 you could disable HDMI and DP handling of the monitor detect signal.

Sadly MS figured we all wanted to have to shit move around as soon as you use a KVM.

(Also, there's usually a 90% chance that windows will not correctly handle the monitor reconnecting without having to either power cycle the monitor or using the video card's 'really truly scan for monitor changes' feature.)

That is a software decision. The nice thing about DisplayPort is that now we can find out if the monitor is on or off and connected or not. It is software's decision to move everything away when the monitor is off but still plugged. I agree this is a bad decision.

The correct thing to do is likely to //ask// the user what they want, on one of the working screens.

If the alternative is waiting for 3 seconds, bothering the user is a bad thing to do.

They absolutely could add a settings toggle. This has been a huge annoyance since DP and HDMI arrived at the scene.

This is a pretty common occurrence for me on macOS with external monitors. I have thunderbolt going to a dock, then displayport from the dock to the monitors.

Waking from sleep will periodically just not find a monitor at all, or they will come up with the wrong positioning (left and right swapped). If I turn a monitor off, the other one (and the laptop) do some sort of resync operation that interrupts the display. It's annoying, but not something I would expect the industry to consider a priority; I'm not really sure it's a monitor issue at all.

I have the same problem! My 2018 MBP can't seem to communicate with my Dell U3415W monitor reliably at all. Sometimes the monitor comes on when I touch the keyboard and everything is fine. Sometimes I have to "fake" a sleep cycle by shoving the mouse into the corner of the screen. And sometimes I have to go through a whole process of turning the monitor off/on, opening the laptop lid, disconnecting the Thunderbolt cable, and anything else I can think of. sigh it seems like this shouldn't be a problem in 2019.

Same issue here, been like this for > five years. Almost like no one at Apple uses multiple monitors.

I just started using triple monitors, one is a TV that sits behind me turned off most of the time, but still active enough to not be considered unplugged. When I physically unplug a monitor, Windows loves to put all the windows on the TV desktop, resize them down to the resolution of the TV, and then proceeds to do stupid things like open all new instances of File Explorer in the TV desktop.

So yeah, it's better than when off really meant off and ports lacked cable detection.

It's terrible on mac. I constantly have one monitor that just refuses to show content until I unplug/replug multiple times or open/close the laptop lid. It's really silly how long this has been a problem and Apple hasn't touched it.

I've had no problems when on a desktop with both monitors plugged into similar interfaces. When you've got one on VGA and one on DisplayPort, or a local laptop display and a VGA on a dock and a DisplayPort also on the dock...it gets confused. Use seems to have largely corrected the VGA monitor + laptop combination, that usually works OK, but digital/daisy-chained combinations with laptops and docks are definitely buggy.