By the way, any suggestion of making the QQ distinction with markup is ruled out by the principle recently expounded on the main Unicode list that separate markup cannot be applied to combining characters.
Isn't this need of allowing separate markup on combining characters addressed by the current proposal to encode a invisible base character (IBC), so that markup can be applied to a non defective combining sequence?
I understand that this proposed new character would more likely be used to allow rendering isolated combining marks, without needing to encode their spacing variant, but the sequence <IBC,combining mark> (now possibly enclosed in markup) could become a candidate for possible ligaturing by preceding it by a ZWJ, or for word-wrap exclusion with a leading WJ...
