I usually use "Verdana" font in mIRC, which is set to resort to "MS PGothic" and then to "Arial Unicode MS" when the characters are not present. These settings are part of the standard font linking provided by Windows 7. But, whenever I encounter certain characters, for instance, this one: [〜] ('WAVE DASH', U+301C), mIRC would change all the characters that are not found in Verdana to those from Arial Unicode MS. It makes this change irreversible, Arial Unicode MS overtakes MS PGothic in all channels at once, it can't be cured by /clear or by closing any inner windows. Verdana's characters stay as they were. If I change the font to Tahoma/etc, it doesn't help. The only way to fix fonts is restarting mIRC. Since Arial Unicode MS is the least readable font out there, especially for Asian characters, this is very very annoying.
Since font linking settings do affect fonts in mIRC--changing "MS Pgothic" to "Meiryo" in the OS font linking settings does change it in mIRC until [〜] is encountered--I suspect that mIRC is trying to do some font linking on its own. Maybe it is possible to disable this behavior altogether and let the OS decide what to display?
mIRC 7.22
