The Problem: New windows and freshly-launched apps (seemingly) arbitrarily push new windows or the app itself to the second monitor.

How do I prevent the seemingly random issue of newly-invoked/-launched apps, dialog/modal windows, and other random app windows from pushing to that other screen? -- I do not want all apps to be pulled from this screen nor do I want them to never open there, if I've assigned there either via another app or by putting it there and then quitting such that the window location would be remembered for the next invocation.


I've had the same setup for 18+ years, since 10.2 or so when I jumped from legacy software on OS9 to embracing OSX. I have a primary monitor which is part of my Mac system (previously a TiBook, and then a 17" HR MBP, and now a 27" iMac) with an extra monitor (previously a sweet Sony CRT (the best crt I ever saw) and for the past 11+ years a 24" Samsung which is starting to show its age)... I also often use my iPad as a third monitor via Wired XDisplay (https://www.splashtop.com/) for specific uses (video streams, text content scratchpads, etc), but it's been happening since long before I started using this on rare occasions.

The problem isn't specific to macOS version, but I'm currently on 10.14 (again for legacy 32-bit software issues). It's been happening for years with seemingly no rhyme or reason. Just giving as much info as possible to limit "guesses" on causes and solutions. You know what I've tried and didn't work. I'd say this started maybe a year or two ago when I started noticing it, so likely back on 10.13 at least.

I use TotalSpaces2 (http://totalspaces.binaryage.com/), but I've reproduced the problem often without TS2 being installed. I've also confirmed that I do not have the "Automatically rearrange Spaces based on most recent use" setting checked in System Prefs > Mission Controlas suggested in several similar questions found here in SE and at the apple discussions.

I have a custom arrangement in my System Prefs > Displays pane, I use Wraparound (https://www.digicowsoftware.com/app/Wraparound), no longer use Moom but it occurred during and after ending use. I now use Divvy (https://mizage.com/) but, like the other apps, it does this with and without it being running.

My TS2 arrangement is a 2x2 grid on my primary monitor and a single screen on my external which never changes. It's a perfect setup to allow me to move things from one space to another without having to actually having to bring it over. MY TS2 settings also include several app settings that require certain apps to live ONLY in certain spaces.

What I've tried:

  • I know that if I invoke the Dock via mouseOver within one screen or the other then anything in perpetuity should consider that window to be the primary. When this happens, I usually do this to prevent additional instances of the issue. Sometimes it doesn't matter and anywhere from minutes, to hours, to days later, it'll resurface. (Yes, if nothing is wrong, I use scripts to clean my caches and purge ram and might leave my mac up and running for weeks or even months.) I don't use the Dock for anything, ever, as I launch everything via Quicksilver and the only times I touch the Dock are to fix the above issue, or by accident (I have it at the smallest size and auto show/hide to reduce the likelihood of this happening, but it does from time to time). I lied, I might sometimes grab a file and drag it to the open app in the Dock to bypass the system compiling all potential apps if I would otherwise open an app via the contextual menu "Open with..." item.
  • I will sometimes quit that app in question, re-launch it fresh, move it where I want it, quit, and then re-launch and it tends to stay put for a good length of time.
  • Searched and found dozens of issues that are similar in that they deal with second or third monitors not respecting the order of things, or are very rudimentary and not complex or as random as this issue appears to be.

[Added Screencaps]

System Prefs -- Mission Control

  • 1) Do you have "Displays have separate Spaces" on or off in System Prefs > Mission Control. 2) When you drag an app to a Space [Desktop], do you lock it there using right-click/Options in the Dock?
    – Tetsujin
    Nov 4, 2020 at 7:50
  • @Tetsujin ... Yes to "displays have separate spaces" No to locking apps when dragging them to desktops. the only controls I use for locking apps to a window are through TotalSapces2 I'll try to edit the OP to add screencaps of relevant settings, too.
    – Jeremy
    Nov 5, 2020 at 0:10
  • Basically,. they're the two things you have to change to get the window behaviour you require. I don't know how all the extra 3rd party stuff is going to mess things up, though, so I can't provide an answer.
    – Tetsujin
    Nov 5, 2020 at 8:39
  • yep, thanks for the input @Tetsujin... I assumed it would tough to track down with at least TS2 being in the equation, but the other stuff isn't an issue, I assume. I don't go long enough with TS2 to know if it has any interference or not. seems like there's no real rhyme or reason to timing when it happens. If it had to do with something regarding a reboot where the second screen items loaded last so it made that the priority, that much I would understand. Sometimes it happens when I've simply switched apps, or even just watched away for a lunch break. Trying to track it down...
    – Jeremy
    Nov 5, 2020 at 22:16


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