Please test in as many browsers as possible and mention in a comment which ones you've used.

1. Using any user account, log in and access your calendar.
2. Add a new user event to a single date in the current month,  setting the start time as 8 am.
3. Verify that it appears correctly with your chosen day and time.
4. Click and drag this event to a different day in the same month.
5. Verify that the event now appears on this different day.
6. Click to edit the calendar entry to verify the time is still 8 am.
7. Repeat the test with an event spanning three days.
8. Drag the event from any of the days, verifying they all move correctly together and that the display wraps into the next week if the move goes into another week.
9. Repeat the test with a single event which is repeated over three consecutive weeks.
10. Verify that each of the three events can  be dragged and dropped separately, behaving as for a single event.
11. Click to delete an event and verify that you can still delete all three events together.