I'm still on the public Yosemite beta program. Their current beta update broke the Wi-Fi on identical MacBooks again, so I've held off on upgrading.

Imagine that happening at Apple HQ.

On the same topic, I heartily recommend iOS folk with external BT keyboards try turning on Airplane mode with the keyboard on and then fiddling with the home button.

For me, it sometimes pops up the "secure" (black) on-screen keyboard WITH MY LAST PASSWORD AS A SUGGESTION.

I'd love to know if that's common to everyone with the latest iOS public release.