public boolean hasHelpContent() {
        return helpContent != null
                && !SafeHtmlUtils.EMPTY_SAFE_HTML.equals(helpContent)
                && !NullSafe.isBlankString(helpContent.asString());
    }
Set the HTML content of the help popup.

@param helpContentHeading The heading to show at the top of the popup
@param helpContent        The help content inside the popup
stroom-core-client-widget/src/main/java/stroom/widget/help/client/HelpButton.java