70-200 2.8 IS mode and framing

My new 70-200 f/2.8 IS will be here in the morning, and the IS mode selector for panning got me thinking about an IS issue. This isn't directly concerning panning technique, but I am wondering about the IS effectiveness in portrait orientation considering that the IS mode selector helps with up/down movement. Basically, is the IS (mode selector) equally effective when the camera is in either portrait/landscape orientation??? Portrait orientation shooting a race car using the far left focus point... as an example.

I hope the question makes sense!

Orientation will make no difference I use it all the time in portrait mode for indoor sports. Now fast panning like autosports I couldn't tell you how effective it will be. But 'human' speed panning slightly helpful.

Thanks for repyling.

It's the mode selector in portrait orientation which I am wondering about, the race car was just an example. Are you using the mode selector for indoor sports? I don't mean IS on or off switch, unless you understood me correctly the first time.

I'm just assuming there is some kind of gyroscope in the lens that determins whether the camera is in portrait or landcape which tells the mode selector system (mode 1 or 2) what up and down is??? Or should I not bother with the mode selector in Portrait???