The 'chooser' modules sets the thin section to be displayed. Zoom and pan within the 'hand-lens' view by clicking and dragging, or by using the Zoomify controls.
Click on the 'arrow' button to select the 'measurement' mode, and then click on both sides of the object to be measured.
Click on one of the rotation points to select the dual petrological view, and then drag within the petrological view to rotate.