Dear FD, I've just discovered that if you press Switch HUD Mode whilst in the DSS, you exit the DSS and are switched to Combat mode, but pressing Switch HUD Mode whilst in FSS does nothing.
I accidentally discovered this whilst trying to bind the same key to Toggle Back/Front View as to Switch HUD Mode and received a warning - I had expected to be able to do this, as it should not be possible to switch HUD modes whilst in the DSS view (seeing as it can only be used in Analysis mode). On the plus side, I guess it's handy if you are interdicted, for example, whilst in DSS view as you can exit the view and switch to combat mode with a single key press. In which case, I would suggest being able to do the same whilst in the FSS.
I accidentally discovered this whilst trying to bind the same key to Toggle Back/Front View as to Switch HUD Mode and received a warning - I had expected to be able to do this, as it should not be possible to switch HUD modes whilst in the DSS view (seeing as it can only be used in Analysis mode). On the plus side, I guess it's handy if you are interdicted, for example, whilst in DSS view as you can exit the view and switch to combat mode with a single key press. In which case, I would suggest being able to do the same whilst in the FSS.