Need to focus away from date field after editing to get "Save" button to be enabled

Original issue 100 created by adam_winer on 2013-06-30T06:01:20.000Z:

DatePanel is currently pretty bad about detecting changes in the Year/Day fields. You ought to be able to just type and have "Save" automatically enabled.

(Unfortunately, FormattedTextField makes this more of a challenge than it should be, as it keeps changing the text out from under itself.)