WD TV Remote 'Back' Button and HDMI-CEC Control Question

The question wasn’t about emulating all of the function of the WD TV remote.  The question is around HDMI-CEC control and whether the ‘Back’ button on the WD TV remote should have a corresponding command on the controlling device’s remote that mimics it.  In the case of the Sony / Samsung, I would assume this to be the ‘Return’ button, on LG I would assume this to be the ‘Back’ button. 

It works this way on other HDMI-CEC enabled devices, I would like confirmation that this is not the case for the WD TV.

Thanks.