This code resulted in the outputConnectionStatus component rendering in disconnected state in ICEfaces 1.8.2:

            <ice:outputConnectionStatus showPopupOnDisconnect="true"/>
<h:form>
<h:commandButton value="Invalidate Session" actionListener="#{applicantController.invalidate}" />
</h:form>

public void invalidate(ActionEvent ae){
  ExternalContext ectx = FacesContext.getCurrentInstance().getExternalContext();
  HttpServletRequest req = (HttpServletRequest)ectx.getRequest();
  HttpSession session = req.getSession(false);
  if(session != null){
  session.invalidate();
  }
}

When using this component in ICEfaces 2, the icon renders in disconneted state, but there is also a modal popup (without the reload button)

User Session Expired
Reload this page to start a new user session.

So the default befavior has changed, giving us a modal pane by default now and this seems to overlap with the showPopupOnDisconnect="true" attribute (which brings up a different modal pane with a reload button)