No RichEdit20A window class

[Krzysztof Foltman]

Shachar Shemesh wrote:

>> - MBCS support (and it would be very hard to add)
> Then you are doing something very wrong. Aren't you working in Unicode?

I am. However, I've assumed that one character = one wchar_t, and there 
are no prefix/suffix non-printable characters.

However, I'm speaking about encodings where character size may vary 
depending on a character. Like using utf-8 internally.

All string operations (even benign ones like calculating number of 
characters) become much more complex, instead of O(1) mapping between 
character index (in characters) and character offset (in bytes or 
words), we have O(N).

Chris