@Override
    public void setDirectionEstimator(DirectionEstimator directionEstimator) {
        directionalTextHelper.setDirectionEstimator(directionEstimator);
    }
{@inheritDoc}
<p>
Note: DirectionEstimator should be set before the label has any content;
it's highly recommended to set it using a constructor. Reason: if the
label already has non-empty content, this will update its direction
according to the new estimator's result. This may cause flicker, and thus
should be avoided.
stroom-core-client-widget/src/main/java/stroom/widget/tickbox/client/view/CustomCheckBox.java