I didn't want to log a bug for this yet as I'm not sure if I'm just missing a property setting but while using a DatePickerField if you have the calendar open place focus on the textbox you can type a date and the calendar just sits there open until you either close it with the calendar icon or select a date which would override the date you typed in. I believe it should either close when you hit the enter key or start typing. Additionally you could have the calendar change with typing of the keys to the date being typed but that isn't what I'm reporting here.
Thanks,
Anthony
ExtReact 6.7.0
Browser: Chrome: Version 72.0.3626.121 (Official Build) (64-bit)