Still no sign of a definition of the strange unlabelled black and white button with TV on it!!
If you mean the one to the top right of the OK button it's the "last channel" button - it'll take you back to the last watched channel. It'll also return you to live TV form any menu/app.
If you mean the black/white power key at the top left it'll turn your TV on/off independently of the box (the red one on the top right will turn the box and TV on/off together if one power is enabled in the settings).
My wife complained, quite reasonably, that the new (and very welcome) diagram of the TV360 remote control with descriptors for most of the buttons has writing which is too small and indistinct. Think of the National Health Service protocol for the font and size of text in communications with patients. Virgin Media would lose hands down according to that protocal. So, I have made up - with some difficulty - my own Word file with larger and clearer text which can be read more easily.
Also, on our TV360 remote control the black and while button at the top left hand corner does not do anything at all - is there a way of connecting it to the TV controls (i.e. turning the TV itself on and off) as, apparently, it should be?
We are becoming more familiar with TV360 and enjoy it.