Sometimes you may want to lock your cursor to one computer, temporarily disabling mouse and keyboard sharing. This could be useful you're playing a video game full screen.
To do this, you'll need to press the scroll lock key. This is often in varying places on different keyboards, and you may need to press a key combination to use it (often it'll be paired with the insert key).
Some modern keyboards don't have a scroll lock key. In which case, you'll need to setup a hotkey.