What is that odd key that shows up on the log-in screen keyboard between the Ctrl key and space bar? It alternates between a blue key with a white box and a gray key with highlighted box. It doesn't seem to have any affect.
It's just one of those things in a touch-based world when all you have is a graphic/icon with no text/hint, you are left to try it to see what happens. In the case of an on-screen keyboard, how much damage could you do by pressing such a key?