Issue Summary

The date picker for Custom Fields on cards doesn't respect the language setting from the Atlassian Account. Sunday is always shown as the first day of the week regardless of which language is set.

Steps to Reproduce

1. Set language on your Atlassian account to English UK
2. Add a date Custom Field to a board in Trello
3. Open a card on that board
4. Open the Due date picker (week starts on Monday)
5. Open the date picker for the custom field (week starts on Sunday)

Expected Results

The date picker for Custom Fields should respect the language setting and alter the day the week starts on.

Actual Results

The Custom Field date picker always shows Sunday as the first day of the week.

Workaround

No workaround available