Making the date picker keyboard accessible

The Orbeon Forms date field allows users to type a date, but also to select a date using a date picker. While most people are used to interacting with date pickers using a mouse, touchpad, or a touch interface, the Orbeon Forms date picker also supports doing so with the keyboard:

1. Tab to the date field, if the focus is not already on that field.
2. Hit the ↓ Down arrow key to open the date picker.
3. Use arrows keys to navigate through the calendar; for instance hitting the ↓ Down arrow key takes you to following week.
4. Press ↵ Enter to select the highlighted date.

This makes the date picker more accessible, but also faster to use for power users, especially in cases where you want to enter a relative date, like "a week from now", or "a month from now, skipping to Monday if that date falls on a weekend". Using the keyboard to select a date in the date picker has been a feature of the product since Orbeon Forms 2019.1.