Wow, I updated my windows (just got prompted to this morning) and the whole thing is resolved. "don't do that" had been my working solution for months (a year maybe?) before I finally got around to reporting it. After noticing that the windows shortcut worked for other full-screen games but not ...

In full screen mode, when using the Windows 10 hotkey Win+Shift+LeftArrow (to swap Factorio to the from the right monitor to the left monitor) the computer "freezes" or "locks up" -- that is, Factorio moves to the other monitor but then everything is frozen and non-responsive indefinitely (Factorio ...