The Mac Plus had modern multi monitor support in 1986: https://www.youtube.com/watch?v=slY_F1MxGlk #VintageApple #VintageMac #RetroComputing
Discussion
nostr:npub1vr4dqq5vzpz0kaavv3lc3098jmfzrpdtj79dazpemytqw4ansf0q2d92wq Seeing Mac 2's do it in ~89 was still damn impressive - having windows split across monitors of different colour depth and resolution is still magic today.