If there is no datetime, then it should be fa-calendar-plus-o to show that user may add datetime here. Click on it should do the same action as a click on the field itself - i.e. open the datetime picker.
If there is datetime then the icon should be as it is now fa-calendar-times-o and should work as it works now - i.e. clears the field.
If there is no datetime, then it should be fa-calendar-plus-o to show that user may add datetime here. Click on it should do the same action as a click on the field itself - i.e. open the datetime picker.
If there is datetime then the icon should be as it is now fa-calendar-times-o and should work as it works now - i.e. clears the field.