public void removeStyleFromDates(String styleName, UTCDate date) {
        styler.setStyleName(date, styleName, false);
        if (isDateVisible(date)) {
            getView().removeStyleFromDate(styleName, date);
        }
    }
Removes the styleName from the given dates (even if it is transient).
stroom-core-client-widget/src/main/java/stroom/widget/datepicker/client/CustomDatePicker.java