Dual Monitor issue

I have the Win 10 version of Minecraft and a dual-monitor setup. I run MC on my primary monitor, and inevitably, during navigating in the game my mouse will stray onto my secondary monitor. And, whenever I click my mouse button, MC is kicked to the main menu and I am left to scramble to click the "Resume Game" button and avert whatever catastrophe is befalling me in the game (usually being attacked by some subterranean creepie).

I have tried both windowed and full-screen mode. Both still don't lock my mouse onto the primary screen. I have tried changing monitor "position" in display settings to no effect. I really don't want to roll back drivers as I have other games that require the latest video drivers. Equally, I think it would be kind of silly to have to unplug one of my monitors to play. I am at a loss.

Sorry if this is a common problem with an obvious fix, but I did scan the boards here, and while I found some vaguely similar issues, I found nothing quite matching this issue. Thanks in advance!!