For each button in a menu it's possible to set where the focus should jump when one of the direction keys on the remote are pressed. Besides the "auto" option this can be all other buttons in the same menu. What I am missing is an option to simply forbid using a specific directional key - there is no explicit "none" option and the button itself is also not available. Sometimes "auto" will provide this behavior (called "auto (none") in that case), but not always.
Please add a "none" option to the list of possible focus targets. This option should always be selectable and simply ignore the key press.