Describe the bug
It seems that there's a bug while trying to use the date picker component, and depending on the default language selected. For example, while trying to submit a form that contains a date picker field, this specific field won't be able to be properly filled due to a JS issue.

To Reproduce
Steps to reproduce the behavior:

1. Create / use a registration form with a date picker field
2. Switch the default Indico language to Japanese
3. Click on the date picker field

Expected behavior
The JS issue should now occur, and the calendar won't appear from the user view. Even when trying to fill the mentioned field manually won't work as expected.

Screenshots