public LeafValueEditor<UTCDate> asEditor() {
        if (editor == null) {
            editor = TakesValueEditor.of(this);
        }
        return editor;
    }
Returns a {@link TakesValueEditor} backed by the DatePicker.
stroom-core-client-widget/src/main/java/stroom/widget/datepicker/client/CustomDatePicker.java