Calendar widget should be clickable

On the metadata edit form, the calendar widget is not clickable. It gets clickable after a form validation error though.
To reproduce:

1. Open the Drive metadata edit form.
2. Click on the calendar icon of the Expiration date.
   -> Nothing happens.
3. Type some text in the expiration date and Save.
   -> You get a validation error.
4. Click on the calendar icon.
   => The calendar is displayed.