Hei,
I do not know if this is a bug.

I use server irc.estirc.net and it allows öüõä alphabet.
If someone's name is Õun, and I press õ + tab, then nothing will happen. If i write Õ + tab it works.

Is it possible to do that: õ=Õ, ö=Ö, ä=Ä and ü=Ü.
Highlight same problem. I set my name "Õun". If someone says Õun it works. If someone says õun its not highlighting.
Highlight setting: $me

I think that this is a problem in mIRC?

You're correct, this is an issue with mIRC and the way it handles unicode.



simply does not print 'ok'.

Similar issues have been reported in the past.

Is õ actually the lower-case version of Õ (just like o is the lower-case version of O)?
One common problem with unicode and the likes is that some letters are not the same when lower-cased; mostly the turkish I is mentioned (with &#305; <-> I and i <-> &#304;).

Although, it's entirely possible that the code points actually work as upper/lower-case for those two, and I'm as wrong as mIRC here

Edit: oh, nvm, just tried it with the Ä on my keyboard, and it's actually not considered equal.

Edit2: Apparently the forum software doesn't like those characters either; the &#304; turns into &#304; when I edit again)

Exactly.
õ is lower-case version of Õ

õ is lower-case, Õ is upper-case
ä is lower-case, Ä is upper-case
ö is lower-case, Ö is upper-case
ü is lower-case, Ü is upper-case

Yes, here is one post where the problem is fully explained https://forums.mirc.com/ubbthreads.php/ubb/showflat/Number/240374

Such a change might not be that easy to do.

It's actually not difficult, it's just a matter of calling the right APIs for string comparison:

https://msdn.microsoft.com/en-us/library/windows/desktop/dd317761(v=vs.85).aspx

I am aware of this issue, unfortunately it is difficult to fix as it would require changes to hundreds of routines for consistency. For example, in the hilite feature alone, changes would be required in the wildcard matching routine, the regex matching routine, the string search routine - and not just the string comparison routine. Multiply this across hundreds of other routines. Also, it is not clear cut whether Unicode normalization (and of which form) should be used everywhere, as it can have security implications. On top of that, there will be an inevitable slow down across all features where CompareString() is used, so routines that use it would need to be carefully optimized. This is on my to-do list but it is a major project. Thanks for your comments everyone.

Note: If anyone has had experience with Unicode normalization/best fit/transcoding/mapping/security issues in applications and recommended practice, your input would be appreciated.