The panorama opens in auto-pan mode. Click anywhere in the picture to stop the scroll. Click the
button to
resume auto-pan. Click
the plus 
button, then
click once or click and hold within the photo to zoom in. Click the minus
button, then
click once or click and hold within the photo to zoom out. Click the 'cross
hairs' 
button to
return to normal viewing and allow you to manually scroll with your
mouse.