There's a long history to this. The original schema spec was inconsistent
about whether "-" had to be escaped or not; they then issued an erratum
saying it had to be escaped; this erratum was later withdrawn. It looks like
you are using a schema processor that implements the erratum that was
subsequently withdrawn.

Michael Kay 

> -----Original Message-----
> From: xmlschema-dev-request@w... 
> [mailto:xmlschema-dev-request@w...] On Behalf Of Wolfgang Jeltsch
> Sent: 15 September 2006 20:37
> To: xmlschema-dev@w...
> Subject: schema for XHTML 1.0
> 
> 
> Hello,
> 
> the schema for XHTML 1.0 Strict which is linked to from 
> http://www.w3.org/TR/xhtml1-schema/ and whose URL is 
> http://www.w3.org/2002/08/xhtml/xhtml1-strict.xsd seems to be 
> incorrect.  
> XMLmind's XML editor outputs the following validation errors 
> upon loading this schema:
> 
> 	[1]
> 	cannot derive simpleType by restriction: 
> "([-+]?(\d+|\d+(\.\d+)?%)(,\s*[-+]?
> 	(\d+|\d+(\.\d+)?%))*)" invalid value for pattern facet: 
> character "-" must be
> 	escaped with "\" in this context [st-props-correct.1]
> 
> 	[2]
> 	cannot derive simpleType by restriction: 
> "([-+]?(\d+|\d+(\.\d+)?%))" invalid
> 	value for pattern facet: character "-" must be escaped 
> with "\" in this
> 	context [st-props-correct.1]
> 
> 	[3]
> 	cannot derive simpleType by restriction: 
> "([-+]?(\d+|\d+(\.\d+)?%)|[1-9]
> 	(\d+)?\*)" invalid value for pattern facet: character 
> "-" must be escaped
> 	with "\" in this context [st-props-correct.1]
> 
> What's the reason for this?  Is escaping the - characters 
> enough to get a correct schema?
> 
> Best wishes,
> Wolfgang
> 


From wolfgang@j... Fri Sep 15 19:56:16 2006
Received: from lisa.w3.org ([128.30.52