Problem with date pickers and i18n

[rolandgeider]

There's a problem when editing date fields that already have a value. The HTML standard expects the format for the date to be ISO860, i.e. 2020-12-30. This is a problem when the language is changed and the value is formatted differently, e.g. 30.12.2020.

All fields that use Html5DateField are affected. A possible solution is probably to overwrite django's template for it and manually making sure the date is correctly formatted django/forms/widgets/date.html but there might be others (I would find it strange that nobody else had this problem before)