I have a Master mouse and keyboard, and I use the flow option to move between two computers (which is a great feature). I use the option to also toggle the keyboard over and to use the CTRL key option so that it doesn't just switch automatically when I hit the side of the screen. I noticed that the computer it switches to then sort of "holds down" the control key as if I am still pressing it, so I have to press it again to "unlock" it to use the keyboard.