HP 16500L Installation And Service Manual page 19

Using the HP 16500B X Window Interface
Duplicating Front-Panel Knob Movement
Hold down the center mouse button, and move the mouse up or to the
right to duplicate clockwise knob movement; move the mouse down
or to the left to duplicate counter-clockwise knob movement.
Or, use the keyboard's Shift-up or -right arrow keys to duplicate
clockwise knob movement; use the Shift-down or -left arrow keys to
duplicate counter-clockwise knob movement.
2-3