Unexpected behavior of inference locking with two inputpoints

[Eneroth3]

The Ruby API docs state the following.

# Lock inference to X axis.
# The points can be anywhere; only the vector between them affects
# the result.
view.lock_inference(
  Sketchup::InputPoint.new(ORIGIN),
  Sketchup::InputPoint.new(Geom::Point3d.new(1, 0, 0))
)

This is untrue. The points define a line in space that inference is locked to. Not just a vector.

This tool can only lock inference onto the model coordinate axes, not parallel to the axes as the comment suggests.

class TestTool
  def initialize
    @ip = Sketchup::InputPoint.new
  end

  def draw(view)
    @ip.draw(view)
  end

  def onKeyDown(key, _repeat, _flags, _view)
    case key
    when VK_RIGHT
      lock_axis(0)
    when VK_LEFT
      lock_axis(1)
    when VK_UP
      lock_axis(2)
    end
  end

  def onKeyUp(key, _repeat, _flags, _view); end

  def onLButtonDown(flags, x, y, view); end

  def onMouseMove(flags, x, y, view)
    @x = x
    @y = y
    do_pick(view)
  end

  private

  # Extracting the picking from mouse move allows the input point to be updated
  # immediately once the inference lock is released.
  def do_pick(view)
    # May get called as tool is activated, before the first mouse event
    return unless @x
    return unless @y

    @ip.pick(view, @x, @y)
    view.tooltip = @ip.tooltip
    view.invalidate
  end

  # Lock the tool inference to a drawing axis.
  #
  # @param axis_i [0, 1, 2] 0 = red, 1 = green, 2 = blue
  def lock_axis(axis_i)
    model = Sketchup.active_model
    direction = model.axes.axes[axis_i]
    model.active_view.lock_inference(
      Sketchup::InputPoint.new(ORIGIN),
      Sketchup::InputPoint.new(ORIGIN.offset(direction))
    )
  end

  # Lock the tool inference to what is currently hovered.
  def lock_hovered
    Sketchup.active_model.active_view.lock_inference(@ip)
  end

  # Unlock any tool inference
  def unlock
    view = Sketchup.active_model.active_view
    view.lock_inference
    do_pick(view)
  end

end

Sketchup.active_model.select_tool(TestTool.new)

If you change the inference lock to use the input point from the mouse cursor, you can lock along the line the inputpoint is on, as you would expand from a SketchUp tool.

class TestTool
    def lock_axis(axis_i)
    model = Sketchup.active_model
    direction = model.axes.axes[axis_i]
    ### model.active_view.lock_inference(
    ###   Sketchup::InputPoint.new(ORIGIN),
    ###   Sketchup::InputPoint.new(ORIGIN.offset(direction))
    ### )
    model.active_view.lock_inference(
      @ip,
      Sketchup::InputPoint.new(@ip.position.offset(direction))
    )
  end
end

[Eneroth3]

Observed behavior goes back to SketchUp 6, suggesting this is a documentation issue and not a regression.

(For SketchUp prior to 2017, replace model.axes.axes with [X_AXIS, Y_AXIS, Z_AXIS].)