1
I know it's been more than a year but still answering it as I am sure someone will stumble upon it in future and so Answering for them.
The basic issue is that the datepicker is not working with dynamically created input field as Magento copies this input text field from a hidden element as you select action from dropdown.
However, I don't have a solution ...
Only top voted, non community-wiki answers of a minimum length are eligible