The video card in one of my computers kept ignoring the primary monitor settings. I have two computers and two monitors. Each computer has dual video outputs, and they feed through a pair of KVM switches. This means that either computer can use both monitors, or one machine can have the primary monitor with mouse and keyboard while the other still displays on the secondary monitor.
Not a common setup, but it works for me. Except, one computer started forgetting its monitor settings. At power-up, it would display only on the secondary monitor, which is an old CRT unit. Most annoying.
After playing with drivers, software, and settings, the ‘light’ finally dawned:
If the video card doesn’t ‘see’ a monitor on the digital port both ports when it powers up, it reverts to default settings. This provides ‘least common denominator’ functionality for the system.
Son the problem was self-inflicted: As long as I switch the monitors to that computer before starting it, everything’s fine. As soon as the boot screens show on both monitors, I can switch back and continue using the other computer.
It’s not a bug, it’s a feature!