Center Button Zoom / Scroll Wheel

[elwuero]

I am not sure how I did this but while viewing some web pages today on Diamond I was zooming in and out using the center button "virtual wheel" when all of a sudden instead of zooming in and out I started scrolling the page and the zoom no longer worked.

I looked in manual and played with Diamond trying to find an option to switch from one function to the other but no luck.

Does anyone know how to switch from one to the other?