Respondeat superior, or vicarious liability that employers face for their employee's torts, has always been limited to acts committed in the scope of employment in furtherance of the employer's purpose. Here, the Supreme Court and Title VII limit the application respondeat superior to form liability for the company to supervisors. Who qualifies as a supervisor has generally been those that can hire, fire or punish. In addition, some courts have found that those that control the day to day activities are considered supervisors. Generally those supervisors are mid-level or bottom-level managers who lack the power to hire employees.
As the LA Times article notes, the Justices were very skeptical of both expanding respondeat superior to a "day to day" supervisor and the facts of the Vance harassment claim. It is, based on the oral arguments, not looking favorable for he Court enlarging who can victimize an employee and who is responsible for that harm.