When scheduling a new job, switching the new job dialog to Advanced tab allows to enter additional job parameters alongside the mandatory job parameters exposed under the Basic tab.
In order to do so, each additional parameter is added by clicking on Add Parameter button after which a new row is added to the job parameters table and waits for edit of new parameter key/value pair.

However, when Add Parameter button is clicked on, the new row in not added until a follow-up mouse action is performed.