https://bugs.winehq.org/show_bug.cgi?id=41797
--- Comment #9 from Rafał Mużyło galtgendo@o2.pl --- (In reply to Dmitry Timoshkov from comment #8)
They are reset, but they clash with the values set from another process. And since the locale dependent font mapping in registry is prefix-global you can't expect that once one app has changed a vital locale setting another app won't break because of that.
Wouldn't some kind of caching (per-app) those values be possible ? After all, in Windows, while AppLocale didn't cover all the cases, it did suffice quite often. I'm not saying it would be easy, cause (AFAIU) it would involve treating certain regkeys differently than the rest, but that doesn't have to mean it's impossible.
I wouldn't WONTFIX it too early, perhaps it's time to tinker a bit more at wine locale handling; after all it's not the only locale dependent problem (you do recall string collation should be - but currently isn't - locale dependent ?)
If I recall correctly the Wine policy for patch acceptance didn't change since then: the patches are welcome (they sometimes get ignored, but that's a different problem).
...and as I've said back in that bug, not only would that require something like icu, but would be somewhat over my programming skills: I suspect a significant performance hit, which I don't expect to be able to compensate for and am not sure of the proper place for checking the locale value (most likely it would involve caching the startup value).