Shifting the times of an entire animated marker

If you change the time of an animated marker's waypoint, it just changes the waypoint times between that waypoint and the surrounding waypoints which are timed. But what if you want to shift the entire marker?

For instance, an animated marker starts from time +1 hour and finishes at +3 hours. Instead, you want to shift it to the start of the map so that it runs from 0 hours to +2 hours.

To do this, shift the time of the very first waypoint. When you do this, a dialog will pop up asking you whether you want to shift just that waypoint's time, or shift the entire marker.

In our example, changing the first time to 0 hours and choosing 'entire marker' will do what we are after.