tFocus: go.Spot.Left,
                  alignmentFocusName: 'BAR'
                })
                  // the indicator (a bar)
                  .add(
                    new go.Shape({ name: 'BAR', fill: 'red', strokeWidth: 0, height: 8 })
                      .bind('fill', 'color')
                      .bind('desiredSize', 'value', (v, shp) => {
                        var scale = shp.part.findObject('SCALE');
                        var path = scale.findMainElement();
                        var len =