How do I engage the Mouse Grid feature?

[hepcat72]

The website says "An application's keyboard navigation support getting you down? Use Mouse Grid (right) to quickly and easily jump the cursor around the screen and click on what you need."

But how do I do that? Every button on the TV remote operates on the TV and nothing happens on the computer. I know that the CEC adapter is working because the CEC menu on the TV now shows my computer's name and I can do things with the cec-client executable on the command line, like change HDMI inputs and put the TV in standby mode (though for some reason, I can't turn on the TV).

How do I know if my TV/remote is just incompatible or if I just don't know how to activate the mouse grid function? I couldn't find any instructions on how to get the mouse grid to work. Is that something I have to script myself?