If you are running a Linux distro from inside your Chromebook you might have some issues accessing the right click.

I am guessing this is because the Chromebook doesn't have a right click button per-say, just a contextual click by holding down alt when you click.

After much playing about with key combinations I found that using two fingers when you click on the button area will perform the same action as right click.

Hopefully this will help someone else who is hopelessly trying to get a right click menu up!