Add dropdown for Subject field when adding appointment from Calendar if there are too many Services to display at once

Presently, when adding an appointment in the Calendar, if a user has too many services available to them, not all of them will show in the Subject field, forcing the user to search for the name of the service themselves. If the user is new this is not obvious and forces them to go into either a users configuration or the Services page to confirm the name of the service for the subject.
Can we please change this to make it a dropdown in this field that will display all available options.