A friend of mine indicate a posible bug in keys in fullscreen,
In his pano
http://timisoara.360cities.net/fs.html? ... remony.p36
seems manifest often, I didn't manage to replicate in one of mine.
If one select fullscreen then press the arrow key up until the camera is oriented at +90° then press key down after few degrees down the tilting seems to slow down then the keys have not effect further on