Behaviour of the w3c datepicker:
After selecting the date with either mouse or keyboard the datepicker pop up is closed and focus is set on the button.
Behaviour of the ab-datepicker:
After selecting the date with either mouse or keyboard the datepicker pop up is closed and focus is set on the input field.
I suggest to change it and set the focus on the button.
Standard: https://w3c.github.io/aria-practices/examples/dialog-modal/datepicker-dialog.html
Behaviour of the w3c datepicker: After selecting the date with either mouse or keyboard the datepicker pop up is closed and focus is set on the button.
Behaviour of the ab-datepicker: After selecting the date with either mouse or keyboard the datepicker pop up is closed and focus is set on the input field.
I suggest to change it and set the focus on the button.