Time selector sliders in datetime custom fields missing

We currently have two RT builds running 4.4.2. One has RTIR installed. We’ve noticed that the build with RTIR has these time selector sliders within the calendar dropdown that make it obvious to the user that a time entry is available. I would like to have these time sliders available in our other RT instance. Is this handled via config setting or is there something else involved?

I am also wondering this.

When chosing Type: ‘Select datetime’ in a custom field I do not see any time selector sliders, only a calendar.