OverStrike control character

[Richard Wordingham]

On Fri, 19 Jun 2020 03:59:29 +0000
Peter Constable via Unicode <unicode at unicode.org> wrote:

> And your new control character would have the same limitation:
> control characters are default ignorable and don't get rendered.

As a systematic rule, that's incorrect behaviour.  They should only be
ignored if the system doesn't 'understand' them.  So, if the font
selected doesn't support it, it can be ignored, but if it does, it
should be honoured as part of the text.

Of course, there are misunderstandings; I've seen USE implementations
complain about ZWJ.

Richard.