As working with two Arduino boards connected to the same PC without having to connect and disconnect a board at a time to load the firmware?
Connect them both and select the COM port and Arduino board for the board you want ot use.
Thank you very much it was easier than I thought!
You can also connect both, and launch arduino.exe twice. Set one instance to one COM port and the other to the second COM port. Now you can program/upload to both boards without needing to change COM ports constantly.
With multiple monitors, I do this all the time. A recent project had me write software that made several AVR communicate with each other via I2C. So I had one connected with its serial monitor open so I can see what was happening in the code, and another connected on a different port. I can write/upload code to this second one and watch the communications on the first one.