v5 relaxng question

hi,

My documents are usually standalone chapters. 

I get an error when I validate against the V5 relaxng that says

"Expecting  element set, got chapter, line 2"

 

From the spec, it appears that a standalone file has to start with a set, book, section, etc, but not a chapter: 

http://www.docbook.org/xml/5.0/rng/docbookxi.rnc

 

Is that intentional? 

I eventually put the chapters together as a book, but I like to validate the chapters sequentially. 

 

thanks,

--Tim Arnold