Difference between Done on Appointment windows

What's the difference between Done on the middle left window and bottom right window on Appointment.

thank you.

Selecting the 'Done' check box and then clicking OK does the same thing as clicking the Done button (which works with just a single click).

In any case, the 'Done' check box indicates whether the Appointment was done already. So if you 'Done' an appointment next time you open its details window you will see the check box selected.

Thanks,
Dina