When logging in to your Windows 10 device, you might have noticed a square icon in the on-screen keypad or keyboard. What does it do and what is it for? The answer might surprise you. Or not.

The square icon turns on and off highlighting of the onscreen keypad or keyboard when typing in your password. For example, if your pin number is 1234, the buttons don't light up when you tap then numbers. The square icon is located to the left of the number zero on the keypad and to the left of the spacebar on the keyboard. You don't see this option, when a physical keyboard is attached.

Highlighting on the keypad or keyboard provides feedback to the user that a button was pressed. Combined with sound, it feels almost as good as pressing physical buttons. However, some users might feel that it might be safer to turn off highlighting when typing in the pin code or password. We think it's nice to have that option even if most of us will probably not use it.

Do you use that square icon on the Windows 10 sign-in screen? Let us know in the comments!