I use a 2015 15" MacBook Pro with two external displays in the following approximate physical configuration:
+-----------+
| +------------------------+
| || |
| || +-----------------+
| || || |
| || 2 (Primary) || |
| 1 || || 3 (Built-in) |
| || || |
| || || |
| +------------------------------------------+
| |
| |
| |
+-----------+
Displays 1 and 2 are external, third-party displays. Display 3 is the laptop's built-in display. Display 2 is the primary display — the one with the menu bar in Display preferences' Arrangement tab. Displays 1 and 2 are attached to the laptop with two Mini DisplayPort cables attached to its two Thunderbolt ports, and are not daisy-chained — they're attached separately.
When I disconnect and reconnect the displays, there's about a 50% chance that the content that was previously on display 1 swaps with the content that was previously on display 3. When this happens, I typically just disconnect and reconnect both displays repeatedly until the content that was on display 1 is shown on display 1, and the content that was on display 3 is on display 3. The content on display 2 never seems to be moved.
How can I configure macOS to keep the arrangement of displays 1 and 3 correct?
Extra info:
- MBP model: MacBookPro11,4
- Display 1: Dell U2713HM
- Display 2: Dell U3011
Related question, though I don't believe it's a duplicate: Primary display randomly changes
