Interestingly, if your Panda is more than two years old, if you press the button to turn off the stop/start, it will remember this setting until you choose to turn it back on.
If the car is newer, the car will always reset so that stop/start is 'on' each time you start it with the key, so you need to tuun it 'off' agin yourself each time.
Personally I rather like it...
(note: pressing the button to turn *off* stop/start turns *on* the light in the button)