They should do the CAPSLOCK variant (ie, passWORD -> PASSWORD). Why would inversion even make sense? If I type passWORD with all caps, and shift the last 4, it does PASSWORD, not inverted.

If I type passWORD with capslock on, I get PASSword when I apply the identical shift pattern (I literally just did this in this box!). This way if I have capslock on when typing my password, but I got the shift pattern the same, it'll still go but it doesn't wipe out my case changing patterns in terms of password security.

I'm pretty sure this behavior of capslock is pretty common across most platforms, I can't think of a platform it didn't do this on. It worked just now on a few distros of Linux and Windows, I don't own a Mac so I cannot test that for you. What platform does shift not invert the case to lowercase if capslock is on?

Yes, Mac does passWORD->PASSWORD if capslock is engaged. It's possible FB detects this based on your platform - but I can't test as I don't use FB.

That's interesting, thanks for sharing. I don't use Macs too often so I wasn't aware that was the behavior on the platform.

Ah - that is what I remembering, thanks for the clarification.