To Do

You have to do

Zoom In

Roll the wheel forward.

Zoom Out

Roll the wheel backward.

Zoom Extents

Double-click the wheel button.

Pan

Hold down the wheel button and drag the mouse.

Constrained Orbit

Press and hold the SHIFT key and the wheel button and drag the mouse.

Pan (Joystick)

Press and hold the CTRL key and the wheel button and drag the mouse.