Start a time recording at the previous end time

Timesheet segments are in 15m intervals, so if a box is clicked it will start at 00, 15, 30 or 45.

If there is a time entry already recorded on a day, it would make sense for the next entry to automatically begin at the end of this previous entry.

Currently, if I've logged time for a job which ended at 10:50, clicking the box underneath this entry would start it at 10:45 or 11:00.