[Bug Report] Editors with different local default date formats cannot update the revision deadline.

[davidjpurser]

The date picker for revision deadlines seems to default to the computer's standard date format. However, the date is only accepted if this is dd/mm/yyyy format. Editors whos formats are dd.mm.yyyy mm/dd/yyyy or yyyy-mm-dd cannot update the dates.

The result is "Please enter a valid date". Note this is in a standard javascript alert box, rather than a more themed modal or bootstrap error message.

See images below.

Expected behaviour:

• Either the date should be accepted regardless of local date format and correctly converted, or
• The date picker should be forced to use the accepted format.