Question Preventing a specific monitor from becoming the primary display in multi monitor setup?

[PB97]

I have a three monitor setup. Two screens that I'm using for regular tasks and a third mini screen that's used used as part of a case mod to display a custom slideshow and performance data.

If I turn off my two regular displays the case mod display becomes the primary screen, and all of the icons and start bar are transferred to it.

Is there any way that I can stop this form happening and just have it as it is?

I'm using an Nvidia graphics card and an HDMI monitor. Dual Monitor tools is being used to generate the slideshow by switching the wallpaper.

The monitors get turned off because it's a multi use room, and sometimes it's absolutely 100% necessary to switch them off (for example, because there aren't enough power sockets). In order to avoid thread drift, could we please stick to the question rather than looking for alternatives to switching he monitors off.

 

[hotaru.hino]

Windows is usually good about remembering which is the primary display in a given configuration, as long as you do the same exact configuration. And I did a quick sanity check on this, though I only have two monitors to do this with.

Note that "same exact configuration" means the same monitors are plugged into the same ports. If you swap which display goes into which port, Windows will likely do its own thing.

 

[PB97]

Windows is usually good about remembering which is the primary display in a given configuration, as long as you do the same exact configuration. And I did a quick sanity check on this, though I only have two monitors to do this with.

Note that "same exact configuration" means the same monitors are plugged into the same ports. If you swap which display goes into which port, Windows will likely do its own thing.

For some reason I don't get this, if I turn off monitor 1 and 2 it swaps all of the settings, including the wallpaper to monitor 3.

 

[USAFRet]

For some reason I don't get this, if I turn off monitor 1 and 2 it swaps all of the settings, including the wallpaper to monitor 3.

Correct.
Lacking 1 & 2, it must then use #3, the little one.

If you then turn 1 & 2 back on, does it revert back to the main being one of those?
Or does it stay on 3?

 

[Math Geek]

It does that because it's the only monitor left to use. Your default is now gone so windows adapts and uses what it can. I don't know a way around this other than to turn off all 3 screens so it has nothing to use.

 

[PB97]

If I turn 2 back on, nothing happens.

If I turn 1 back on it goes back to being monitor 3 again. The wallpaper changes to my chosen one for that screen.

 

[USAFRet]

I am not sure if there is a way to force it to "never use" a particular monitor, in the face of having no others to display with.

 

[Math Geek]

I have 3 monitors and I can't make it change the behavior. If any 1 screen is on then that's the default for the moment.

If I turn them all off, then it stays with my default and nothing changes. Seems the only workaround that still involves turning off monitors not in use.

 

[thestryker]

Are any of your screens connected via display port? I never had this issue when everything was connected via HDMI/DVI but once DP was added to the mix this happens all the time so I never turn off my primary display and just let it go to sleep.

 

[Ralston18]

I wondered if Powershell could be used.

There are monitor related cmdlets but I, full disclosure, have not worked with them.

Did some googling and although Powershell seems viable I did not find anything immediately straightforward.

For example:

https://dev.to/michidk/changing-the-primary-display-on-windows-by-code-is-easy-right-48df

https://superuser.com/questions/1255950/script-to-switch-primary-display-setting

However, Nirsoft multi-monitor tool appeared in some of the search results - including the above links.

May be worth a look.....

https://www.nirsoft.net/utils/multi_monitor_tool.html

 

[PB97]

Primary is dp, other two are HDmi

 

[thestryker]

There's your answer then. When you turn off a monitor connected via DP it acts the same as unplugging the screen. This does not happen when connected with HDMI.

I have 3 displays connected to my PC: 144hz ultrawide via DP, 60hz 1200p via DP to HDMI adapter, and 60hz 4k via HDMI. I added the adapter in because when the second screen was connected with DP it would rearrange when turned off because the screen connected with HDMI was still detected. Once this display was connected with HDMI this no longer happened. So when my PC is on I always leave my main display on and just let it go to sleep (I turn it off when the pc is off and just got in the habit of turning it on before powering on the pc).

 

[PB97]

So the answer is to put screen 1 and 3 on hdmi, and Screen 2 on dp?

Why do they respond differently when switch off?

 

[thestryker]

I have no idea why DP behaves differently than HDMI when it comes to this sort of thing just something I found out the hard way.

I waited to reply here until I tested something myself and even unplugging the power from my secondary HDMI screen doesn't reorder my displays.

So basically if that mini display is the only one on all the time the PC is it should be the one hooked up to DP, or you could just get an adapter to go from DP to HDMI if you don't need the extra DP bandwidth for any of your displays.

 

[Math Geek]

i've never noticed that either but then i've never tried to do what you are doing. my main screen is DP and the other 2 are hdmi. at times the main screen will rearrange the icons on me after the other 2 are both running. its annoying but never really cared enough to try and figure out if it can be stopped.

hopefully the idea above is the answer for you. guess all thats left is to try it out and see.