@SuppressWarnings("unused") // Bound to UI attr
    public void setHelpText(final String helpText) {
        this.helpText = helpText;

//        // This allows us to have hard coded help in the ui.xml but override it
//        // using helpText, or set helpText back to null to use the hardcoded
//        // ui.xml content
//        if (NullSafe.isBlankString(helpText) && helpHTML != null) {
//            this.helpText = helpHTML.getHTML();
//        }
        updateHelpButton();
    }
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