I was working on a quick app, using Struts 2, Spring, Spring Security, and SiteMesh (3 Alpha 2 for those that care - it's actually pretty good for an 'alpha' tag).
Specifically, I hadn't used the Spring Security taglib before, so I couldn't understand why the tags I was specifying just weren't doing anyrhing. It was as if they were being ignored.
It turn's out, after some significant head scrathing, and swearing that I had fallen foul of web.xml filter ordering. You have to have the SiteMesh filter *after* the Spring Security one, as follows:
... other web.xml stuffspringSecurityFilterChain org.springframework.web.filter.DelegatingFilterProxy springSecurityFilterChain /* sitemesh org.sitemesh.config.ConfigurableSiteMeshFilter ... other web.xml stuff sitemesh /*
If you put them in the order above, ev erything works swimmingly, and the tags are honoured.
Hope that helps.