In the day as well as the week perspective of the calender the left timeline can not be changed - it is just an hourly step and you can not make the time line steps bigger and thus see the entire day without having to scroll down.
steps to reproduce:
1. Select the daily or weekly view.
2. Try to zoom in or out (at the moment they all are 1 hour) to more or less.
It is not possible, nothing happens. If you want to see an evening event you have to scroll the calendar down.
the timeslots in the left timeline get bigger or smaller by zooming in or out. Thus, the viewer would be able to see the entire day at a look or to get closer to all the morning events and have a closer look at them - at the same time with the zooming in/ out the left timeline is adapting the times.