@Override
    public void clear() {
        childWidget = null;
        helpHTML = null;
        helpText = null;
        descriptionHTML = null;
        updateLabelPanel();
        updateDescriptionPanel();
        updateFormGroupPanel();
//        formGroupPanel.clear();
//        formGroupPanel.add(labelPanel);
//        formGroupPanel.add(descriptionPanel);
//        formGroupPanel.add(feedback);
    }
Plain text, any HTML will be escaped.
The helpText attr trumps the {@code <form:HelpHTML>} element.
<p>
To programmatically set HTML help text, use {@link FormGroup#overrideHelpText(SafeHtml)}.
</p>
stroom-core-client-widget/src/main/java/stroom/widget/form/client/FormGroup.java