if (this.options.selection === 'after' && percentage >= positionPercentages[0]) {
                                    this._addClass(this.tickLabels[i], 'label-in-selection');
                                } else if (this.options.selection === 'before' && percentage <= positionPercentages[0]) {
                                    this._addClass(this.tickLabels[i], 'label-in-selection');
                                }