[Feature request] Possibility to flip the board upside down whenever the user wants

If there is already a way to do this, I haven't found it. Maybe I'm distracted :)

I think it would be useful, especially in Tactics trainer. Sometimes you want to see the board from the opponent's point of view.

What do you think? I miss that feature.

The 'f' key does it, but it doesn't seem to work in tactics trainer.