Q: I have an extra display, why my mouse can't cross over to the extra display?

You're using a single display KVM switch, which means it can only handle one monitor at a time. That's why your mouse cursor can't seem to move to the extra display.

Try connecting your mouse directly to a USB port on the front of your computer instead of using the KVM switch.

Note: If you connect your keyboard to a front USB port as well, you might lose some hotkey functionality.