Overview
The title is intentional, because MacOS falls short of actually accomplishing display arrangement in some circumstances.
Circumstances
When multiple monitors of certain brands and models are plugged into a MacBook, the part of MacOS that derives a "unique" identifier for each monitor fails to distinguish between them. The HP E243 is one example, but there may also be other brands/models that reveal this flaw in MacOS' handling of external monitor identification. Since MacOS cannot tell which specific display was previously arranged in a particular position (relative to the internal display, or other external displays, or each other), the overall arrangement sometimes gets mangled. The only common way to re-arrange the monitors is by way of the cumbersome "System Preferences -> Displays" dialog in MacOS.
Remedy
After years of searching for a reasonable solution to this issue, and hoping Apple would get it fixed (but has not as of Monterey / 12.6), I finally found, sorta by accident, a command line utility (the best kind IMO) with the source code published on Github, called DisplayPlacer. DisplayPlacer removes "most" of the annoyance of this Apple MacOS bug. It still requires a manual step (running a command/script) to force displays back into a captured/desired arrangement, but is WAYYYYYYYY better than using the MacOS "System Preferences -> Displays" UI every time.
Steps
- Install displayplacer (brew tap instructions on the github repo)
- https://github.com/jakehilborn/displayplacer
- Arrange displays using the MacOS System Preferences -> Displays (yup... one last time)
- Run displayplacer list and copy/capture the displayplacer command that is printed to the console, which contains all of the distinct display ids, resolutions, refresh rates, and relative positions.
- Create a shell script containing the captured command.
- Whenever MacOS !@#$% the display arrangement again, run the shell script to pop everything back where it is supposed to go.
