> Thanks for the clarification. I probably misunderstood Jon's intention. > But is there a problem if, for example, an application sees the string > <space, space, combining mark> and regularises it (wrongly!) to <space, > combining mark>?
Yes, I was not saying that it wouldn't be sensible to begin a line of text with a spacing diacritic (whether precomposed or created using space or NBSP). I was saying that it wouldn't be sensible to begin a line with a combining diacritic, since that combining diacritic would be combining with a newline character which it's difficult to think of any possible sensible meaning for. Attribute normalisation would change the sequence U+000A, <combining> to U+0020, <combining> which would arguably change the meaning, but changing the meaning of a meaningless construct isn't a problem to my mind.
