The Ladder handle is an invisible handle.  It is triggered by the
middle mouse button in the view port.  Usually, this handle is bound
using the "Bind to viewport handle" RMB option in the dialog.

The Ladder variant is designed to link to floating point values, and
has the default increments of 0.1, 1, and 10.

Parameters:

    parm0-parm9  - The parameters which will be updated by the ladder.

See Also: Step Ladder
