helpText.appendHtmlConstant("<ul>");
helpText.appendHtmlConstant("<li>").appendEscaped("(*): Required attribute");
helpText.appendHtmlConstant("<li>").appendEscaped("+expression: Expressions are supported");
helpText.appendHtmlConstant("<li>").appendEscaped("runtime: Runtime value");
helpText.appendHtmlConstant("</ul>");
StaticHelpPanel help = new StaticHelpPanel(helpText.toSafeHtml());
inner.add(help.asWidget());
inner.add(attributePanel);
inner.add(operationsPanel);
inner.add(childrenPanel);