What's this key on the on-screen keyboard for passwords?

[ilabene]

Hi. I just got my Surface Pro 2 in January so I'm seeing this for the first time. What is it? What does it mean? And what does it do?

 

[borasar]

just speculating here, but if it's for passwords it might show or hide the password your typing in? that should be easy to test

 

[TripsG]

Interesting. I'm on a Surface Pro and I have an emoticons key there. Hmmmm...

 

[troylytle]

It shows/hides the keys as you are pressing them. Not the entire password.

 

[ilabene]

Right. I tried it out before to see if it showed my password as I typed it in but as troylytle said, it stops the keys you're typing from highlighting on the screen. Thanks!