Just noticed that the date picker icon is clickable and causes the mini calendar to pop up when it should be disabled.

To replicate:

1. Navigate to the calendar.
2. Create a new event.
3. Show more to display more form elements.
4. The Duration should be set to "Without duration" by default.
5. Click on the date picker icon for the "Until" field without selecting the "Until" radio button.
6. Expected:
   • The date picker should not come up.
7. Actual:
   • The date picker comes up.

This only seems to happen in the new event modal in the calendar page.