Add option+click on the display menu header and Settings display list to visually identify a display

[waydabber]

Discussed in #3745

^{Originally posted by Jip-Hop December 7, 2024}

Lenovo ThinkVision P40w-20 Issues

I bought this 39,7" 5120x2160 ultrawide monitor and planned on using it in the following 3 modes (while being able to quickly toggle between modes):

1. 5120x2160 in 2560x1080 HiDPI as second monitor
2. 2x 2560x2160 in 1280x1080 HiDPI as second and third monitor
3. 1x 2560x2160 in 1280x1080 HiDPI as second monitor (for when 3 monitors or ultrawide is too much)

The goal is to do this while connecting just a single thunderbolt 4 cable between my MacBook Pro (M3 Pro) and the monitor.

Unfortunately the True Split feature of the screen, which should be able to support the above configuration, only works with Windows. But ‘thankfully’ this monitor supports daisy chaining another monitor via the downstream thunderbolt port. So I came up with a workaround to connect to two inputs of the same P40w-20 monitor with just one cable to the MacBook:

MacBook —> thunderbolt cable —> P40w-20 —> usb-c to DisplayPort adapter —> DisplayPort cable —> P40w-20

Now when I put the monitor in Picture by Picture (PbP) mode I can use both halves of the screen (mode 2) as individual monitors and thanks to BetterDisplay I can disable the right half to work in mode 3.

However I’m still running into some issues.

When I disable PbP, then the MacBook is still connected to the screen through 2 inputs and another 5120x2160 monitor shows up in display preferences. I don’t want to use this screen in mode 1. I can disable this one through BetterDisplay, but BetterDisplay can’t show me which one to disable. There’s no way for me to identify which screen is the one connected directly (thunderbolt) and which one is connected via DisplayPort. They’re called the same with a number suffix. However confusingly this number suffix doesn’t correspond with the number suffix in macOS Display settings.

In the macOS Display settings I can find which screen I’m looking at in the Arrange Displays window. By clicking the screen a red rectangle appears. I then set the thunderbolt input as primary screen and only then I can visually identify in BetterDisplay which screen I want to keep, and which one I want to disable. But this means I need to go through display settings each time I toggle between the PbP and normal setup.

Could BetterDisplay show a red rectangle when hovering the screens from the menubar? That would be a great help to visually identify identical displays.

Thanks for the useful tool and I’m looking forward to any suggestions!

[waydabber]

Related to this: #1759

[waydabber]

Option-clicking on the menu header will flash the display briefly for easier identification.

[waydabber]

Also added to the horizontal header listing under Settings/Displays

[Jip-Hop]

Works great in Version 3.2.2 Internal Pre-Release Build 35906! Although I'd prefer if I could do it with just the mouse. Perhaps a right click to identify? Currently right click doesn't seem to be used in the horizontal header listing menu header.

[waydabber]

If you want to use the mouse only, you can go to Manage Display/Identify...

The right click is rather easy to invoke by an error (especially on a trackpad or magic mouse by less experienced user) and the screen flashing is rather drastic and might cause alarm. Also, the option+click works universally everywhere now there is a display listing (in Settings and the app menu), not just the headers.