I have three displays connected to my mac mini. (I have used Arrangement to make sure they are connected correctly left to right, so mouse movement works correctly.) The leftmost is the primary with the dock. However, the middle display is call "Display 3" and the rigtmost is "Display 2". Even if I swap the cables, it still stays the same, so OSX must remember the displayid. This is a problem because Desktop numbering (in Spaces) are out of sequence rigt to left across the displays. It is also confusing that when you assign an app to a display, you have to remember that 3 is the middle display. I know I could just physically swap display 2 and 3, but can this be solved through macOS Display settings? 🙂
Any suggestion on how one can reassign the numbering of the displays?
Best Answer
This is a very annoying problem and I have not found any official documentation on how to control the numbering of the Desktop on each monitor. However, through a lot of trial and error, I've discovered these rules that will help you order the Desktop numbers.
First, a few key points on how the numbering behaves
If you drag the DOCK from Monitor A to B, you'll end up with the following:
Therefore, by planning the sequence of DOCK position swaps, you can reach the final ordering that you desire.
The ordering may get messed up again if you disconnect the monitors or return from sleep or restart. I have no idea how to 'save' the settings. But at least this will help you reconfigure quickly.