My keyboard doesn't shut off when I press the on/off button and it doesn't say anything about it in the booklet that comes with it. I can still type after pressing the on/off button. But I find that if I hold down the button for a few seconds until the green light turns off, then the virtual keyboard pops up and the keyboard is off and the green light goes away. Is this as designed? Or should I be concerned it isn't working properly? If this is as designed, I don't understand the benefit of holding down the button. I WOULD understand holding the button down to turn it on, but that is not the case. Thanks.