If you want to use an application with reactUI inside an iframe (e.g. embedded into another site), the standard http session handling won't work as usual. To use the application inside an iframe, simply add following in the web.xml of your application:

<init-param>
  <param-name>useInternSession</param-name>
  <param-value>true</param-value>
</init-param>

This will switch from http session management to internal session management. You don't have any limitations.