sitemesh 2 not decorating html

[Peter N. Steinmetz]

I am trying to use sitemesh 2.4.2 under tomcat8 on a small site which consists primarily of html pages. 

I have the sample war running and a small test site which is configured similarly. 

If I have a file named test.jsp, it is decorated properly.

But if I rename the same file to test.html, it is not decorated and the page returns a blank, not an error. 

Any suggestions for debugging this? 

thanks,

Peter