...Combining marks have neutral bidi properties, and several other properties, and so inherit these properties from their base characters. Would this apply also to PUA characters used as combining marks? This would of course be necessary if these combining marks are to be applied to RTL scripts.
BTW, you have been mentioning the combining class; you can have combining marks in the PUA, but they have to have zero combining classes.
By the way, since there are such neutral properties for combining marks, surely these would be more suitable defaults for PUA characters as well, better than the existing defaults which specify particular properties which are useful for some but useless for others.
-- Peter Kirk [EMAIL PROTECTED] (personal) [EMAIL PROTECTED] (work) http://www.qaya.org/