Without the EDID cloner, when you switch the KVM away from the system, it receives a monitor disconnect event. When you switch it back, it receives a monitor connect event. There are OS settings that help make it so that the windows end up back where they started, but not all programs support this well. With a EDID cloner in place, the computer never detects that the monitor shifted at all and so nothing gets repositioned and apps just carry on.