Error setting hours of a recurring event

[clochix]

Create a new event, make it recurrent, come back to the main event panel:

• hours are now displayed in 12h format (with AM/PM);
• clicking on the field display an hour helper (like the calendar) that I'm unable to remove;
• sometime, I'm unable to change the start date: the value is reseted every time I quit the field.

This only happens on recurring events.

[jsilvestre]

Also see #466.

[jsilvestre]

We created a mega-issue about recurring events. See #583.