LibreElec - CEC Keyboard Mapping - Options Menu

I've installed LibreElec on a Raspberry PI and things are generally working well, I'm using HDMI-CEC so that I can use my Samsung TV's remote control this is also working. There's an menu that I need to use the remote control for, I think it's called 'Options' this is what it shows on the screen, menu pops out from the left hand side of the screen?

I therefore thought it would be a simple process of adding:

<yellow>ContextMenu</yellow>

To the xml file:

/storage/.kodi/userdata/keymaps/keyboard.xml

I've removed the exiting entry for the Yellow button my questions are:

Am I editing the correct file?

What is the correct entry to enable the options menu?

Thanks