private void showHelpPopup(final Element element) {
        final SafeHtmlBuilder builder = new SafeHtmlBuilder();
        if (!NullSafe.isBlankString(helpContentHeading)) {
            builder.appendHtmlConstant("<h4>")
                    .appendEscaped(helpContentHeading)
                    .appendHtmlConstant("</h4>");
        }
        final SafeHtml popupText = builder
                .append(helpContent)
                .toSafeHtml();

        ShowHelpEvent.builder(element)
                .withContent(popupText)
                .fire();
    }
Show the help popup. Useful if you want to trigger the help popup from a keydown
on some other widget, e.g. a form group.
stroom-core-client-widget/src/main/java/stroom/widget/help/client/HelpButton.java