Update: Ok..., finally sorted out the problem, the subtitle bar is there (in "video calibration"setting), but was not visible because it is off the bottom of the screen.
It is not reachable with the remote control "mouse", but if you hover at the bottom of the screen (with the mouse pointer) the subtitle position caption becomes active and you can move the subtitle position "up" with the arrow keys on the remote control...
NB: the subtitle position only works with the "fixed" subtitle position in the main settings (player settings), does not work if you select "below video" position, or above, etc...