Yet another macOS iteration that fails to properly support multiple displays

[ideal.dreams]

Running the latest macOS 26 beta on my M1 Mac Studio. I have two displays connected to my Mac via DisplayPort to USB-C. I noticed years ago that I turn on the "displays have separate spaces" option in Settings (Settings > Desktop & Dock > Mission Control > Displays have separate Spaces), window opening behavior fails.

Let me elaborate. I ONLY want Safari to open on my secondary display, never on my primary as a portion of the window is cut off by the dock. One would think this could be simply solved by opening Safari, right-clicking on the app in the dock, selecting Options > Assign To > Desktop on Display 2. And...it is!! After checking that option, quitting Safari, and re-opening from the dock, the window opens on Display 2! How magical! But, just like in the prior version of macOS, this completely breaks down if your displays go to sleep.

When the displays are back on and I open Safari from the dock, it opens on my primary display, Display 1, DESPITE the setting to "Assign to desktop on display 2" still being checked!

The only reliable way I've found to get Safari to open 100% of the time on my second display is to disable the setting "displays have separate spaces," effectively disabling all of the nice window tiling options/features that I want to be able to use.

Am I missing something painfully obvious here that's prompting this behavior? Or is this bug/"feature" working exactly as Apple designed? I don't know how in 2025 macOS still can't functionally support multiple displays in this way.

 

[Bigwaff]

Are both your displays the same brand and model?

 

[CasualFanboy]

The problem is that you're opening safari.

Stop doing that.

 

[!!!]

Am I missing something painfully obvious here that's prompting this behavior? Or is this bug/"feature" working exactly as Apple designed? I don't know how in 2025 macOS still can't functionally support multiple displays in this way.

Apple makes iPhones. The iPhone does not support multiple displays. Therefore, your issue will not be fixed. Apple thanks you for buying the Mac, they hope you'll have lots of fun using iPhone Mirroring and AI writing/photo generation.

 

[ideal.dreams]

Are both your displays the same brand and model?

Yes, both identical.

 

[ideal.dreams]

The problem is that you're opening safari.

Stop doing that.

Ha. Pretend instead of Safari I named any other app. Issue persists.

 

[ebika]

Running the latest macOS 26 beta on my M1 Mac Studio. I have two displays connected to my Mac via DisplayPort to USB-C. I noticed years ago that I turn on the "displays have separate spaces" option in Settings (Settings > Desktop & Dock > Mission Control > Displays have separate Spaces), window opening behavior fails.

Let me elaborate. I ONLY want Safari to open on my secondary display, never on my primary as a portion of the window is cut off by the dock. One would think this could be simply solved by opening Safari, right-clicking on the app in the dock, selecting Options > Assign To > Desktop on Display 2. And...it is!! After checking that option, quitting Safari, and re-opening from the dock, the window opens on Display 2! How magical! But, just like in the prior version of macOS, this completely breaks down if your displays go to sleep.

When the displays are back on and I open Safari from the dock, it opens on my primary display, Display 1, DESPITE the setting to "Assign to desktop on display 2" still being checked!

The only reliable way I've found to get Safari to open 100% of the time on my second display is to disable the setting "displays have separate spaces," effectively disabling all of the nice window tiling options/features that I want to be able to use.

Am I missing something painfully obvious here that's prompting this behavior? Or is this bug/"feature" working exactly as Apple designed? I don't know how in 2025 macOS still can't functionally support multiple displays in this way.

Yeah, that sounds annoying. Have you submitted a bug report in the Feedback app? If you can link to the issue they open, maybe we can pile on to raise its visibility. I think this was one of the reasons I started using Rectangle.app (and before that whatever its predecessor was called) to use keyboard shortcut muscle memory window flinging across displays. I'm with you that we should still push Apple to correct the assign to feature though.

 

[PaulD-UK]

Does this happen with two Apple Studio Displays?

What I’ve found is that monitors such as Dell cause funky behaviour on wake-from-sleep because the display has its own internal
OS which is running its own setup routines and error checking or whatever and is ignoring the MacOS wake-up handshake.

By the time the monitor is ready the Mac has reverted to default settings.

You can’t really blame Apple for not keeping MacOS hanging around checking the wake-up foibles of a variety of third party monitors if that means their own monitors aren’t as responsive… 😵‍💫

 

[ebika]

Does this happen with two Apple Studio Displays?

What I’ve found is that monitors such as Dell cause funky behaviour on wake-from-sleep because the display has its own internal
OS which is running its own setup routines and error checking or whatever and is ignoring the MacOS wake-up handshake.

By the time the monitor is ready the Mac has reverted to default settings.

You can’t really blame Apple for keeping MacOS hanging around checking the wake-up foibles of a variety of third party monitors if that means their own monitors aren’t as responsive… 😵‍💫

Agreed on the quirkiness of 3rd party monitors waking up. At some point, the Mac is still reacting to the state of connected monitors to be able to decide and render elements like where the Dock goes when that quirky display eventually locks in. I'd expect that would be the right time for any "assign to" settings to re-evaluate where the windows should be regardless of how long it took the monitor to wake up. My expectation is based on the Mac remembering the assignment setting is display 2, like OP said. If that setting reverted to default then we could reason that their external display state management isn't smart enough right now. However, it seems like it's either almost smart enough and could have the feature expanded to be smarter, or it's supposed to already be smart enough and it just has a bug.

Either way, submitting feedback will help their Product Managers queue up the request to do something about it (or deprioritize and ignore it).

 

[BrianBaughn]

That kind of stuff is annoying.

While Safari is open, make a shortcut that opens Safari and then sends a keyboard shortcut to move Safari to the second monitor. If there isn't a keyboard command existing you can create one in keyboard settings.

 

[Rastafabi]

Yes, both identical.

That it's possible that it's not only Apple's fault. some manufactures (or only some product lines within a manufacturer= have sloppy firmwares and EDID data, that identifies the display to the OS in exactly the same way with now way to tell the apart by unique identifiers (in certain places). So when the Mac wakes from sleep the display that comes up slightly earlier that time might get assigned display 1 while beforehand it was display 2.

At the same time for the actual display arrangement other identifiers of the displays might be used, so you can't tell that this is what happens.

Apple grew to respect and follow hardware descriptors pretty much to the letter. So much so that it needed to write hardware overwrites for many Macs from another era, as theses did not implement some identifiers (like USB-Port enumeration and mapping) as intended by the underlying firmware standards.

There are actually such remapping files to fix bad firmwares of displays in macOS but they are protected nowadays and cannot be user edited. The display manufactures need to provide them for apple to include them within macOS.

This approach obviously collides in some cases with the ease of use, but it should result in the industry honoring standards better, and proceeding with hardware devices' software and firmware getting ever so better year by year.

Sadly it will always be easier to cut corners so something mostly works rather than actually doing something correctly. And the end users feel this.

 

[CasualFanboy]

Apple makes iPhones. The iPhone does not support multiple displays. Therefore, your issue will not be fixed. Apple thanks you for buying the Mac, they hope you'll have lots of fun using iPhone Mirroring and AI writing/photo generation.

AND the nu eMoJiS